Search Results

Search found 7118 results on 285 pages for 'sam ram san'.

Page 238/285 | < Previous Page | 234 235 236 237 238 239 240 241 242 243 244 245  | Next Page >

• monitor and kill runaway processes using 100% IO?

  - by bleomycin

  Hello everyone, i have a few processes that have to be run at high priority (chrt 98) that will occasionally decide to hard-lock and peg 1 core at 100% (not a huge deal) but more importantly it will use all the IO on a system, so much that its impossible to log into the machine via ssh to kill it or perform any task on the machine that isn't loaded into ram. If i happen to have something like htop already running i am able to end the process fine. Is there any type of utility/way to monitor for this type of runaway process and kill anything that uses 100% of system IO for more than X amount of time? Thanks!

  Read the article

• Problem setting up Master-Master Replication in MySQL

  - by Andrew

  I am attempting to setup Master-Master Replication on two MySQL database servers. I have followed the steps in this guide, but it fails in the middle of Step 4 with SHOW MASTER STATUS; It simply returns an empty set. I get the same 3 errors in both servers' logs. MySQL errors on SQL1: [ERROR] Failed to open the relay log './sql1-relay-bin.000001' (relay_log_pos 4) [ERROR] Could not find target log during relay log initialization [ERROR] Failed to initialize the master info structure MySQL Errors on SQL2: [ERROR] Failed to open the relay log './sql2-relay-bin.000001' (relay_log_pos 4) [ERROR] Could not find target log during relay log initialization [ERROR] Failed to initialize the master info structure The errors make no sense because I'm not referencing those files in any of my configurations. I'm using Ubuntu Server 10.04 x64 and my configuration files are copied below. I don't know where to go from here or how to troubleshoot this. Please help. Thanks. /etc/mysql/my.cnf on SQL1: # # The MySQL database server configuration file. # # You can copy this to one of: # - "/etc/mysql/my.cnf" to set global options, # - "~/.my.cnf" to set user-specific options. # # One can use all long options that the program supports. # Run program with --help to get a list of available options and with # --print-defaults to see which it would actually understand and use. # # For explanations see # http://dev.mysql.com/doc/mysql/en/server-system-variables.html # This will be passed to all mysql clients # It has been reported that passwords should be enclosed with ticks/quotes # escpecially if they contain "#" chars... # Remember to edit /etc/mysql/debian.cnf when changing the socket location. [client] port = 3306 socket = /var/run/mysqld/mysqld.sock # Here is entries for some specific programs # The following values assume you have at least 32M ram # This was formally known as [safe_mysqld]. Both versions are currently parsed. [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] # # * Basic Settings # # # * IMPORTANT # If you make changes to these settings and your system uses apparmor, you may # also need to also adjust /etc/apparmor.d/usr.sbin.mysqld. # user = mysql socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp skip-external-locking # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. bind-address = <SQL1's IP> # # * Fine Tuning # key_buffer = 16M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP #max_connections = 100 #table_cache = 64 #thread_concurrency = 10 # # * Query Cache Configuration # query_cache_limit = 1M query_cache_size = 16M # # * Logging and Replication # # Both location gets rotated by the cronjob. # Be aware that this log type is a performance killer. # As of 5.1 you can enable the log at runtime! #general_log_file = /var/log/mysql/mysql.log #general_log = 1 log_error = /var/log/mysql/error.log # Here you can see queries with especially long duration #log_slow_queries = /var/log/mysql/mysql-slow.log #long_query_time = 2 #log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. server-id = 1 replicate-same-server-id = 0 auto-increment-increment = 2 auto-increment-offset = 1 master-host = <SQL2's IP> master-user = slave_user master-password = "slave_password" master-connect-retry = 60 replicate-do-db = db1 log-bin= /var/log/mysql/mysql-bin.log binlog-do-db = db1 binlog-ignore-db = mysql relay-log = /var/lib/mysql/slave-relay.log relay-log-index = /var/lib/mysql/slave-relay-log.index expire_logs_days = 10 max_binlog_size = 500M # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! # # * Security Features # # Read the manual, too, if you want chroot! # chroot = /var/lib/mysql/ # # For generating SSL certificates I recommend the OpenSSL GUI "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 16M # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/ /etc/mysql/my.cnf on SQL2: # # The MySQL database server configuration file. # # You can copy this to one of: # - "/etc/mysql/my.cnf" to set global options, # - "~/.my.cnf" to set user-specific options. # # One can use all long options that the program supports. # Run program with --help to get a list of available options and with # --print-defaults to see which it would actually understand and use. # # For explanations see # http://dev.mysql.com/doc/mysql/en/server-system-variables.html # This will be passed to all mysql clients # It has been reported that passwords should be enclosed with ticks/quotes # escpecially if they contain "#" chars... # Remember to edit /etc/mysql/debian.cnf when changing the socket location. [client] port = 3306 socket = /var/run/mysqld/mysqld.sock # Here is entries for some specific programs # The following values assume you have at least 32M ram # This was formally known as [safe_mysqld]. Both versions are currently parsed. [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] # # * Basic Settings # # # * IMPORTANT # If you make changes to these settings and your system uses apparmor, you may # also need to also adjust /etc/apparmor.d/usr.sbin.mysqld. # user = mysql socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp skip-external-locking # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. bind-address = <SQL2's IP> # # * Fine Tuning # key_buffer = 16M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP #max_connections = 100 #table_cache = 64 #thread_concurrency = 10 # # * Query Cache Configuration # query_cache_limit = 1M query_cache_size = 16M # # * Logging and Replication # # Both location gets rotated by the cronjob. # Be aware that this log type is a performance killer. # As of 5.1 you can enable the log at runtime! #general_log_file = /var/log/mysql/mysql.log #general_log = 1 log_error = /var/log/mysql/error.log # Here you can see queries with especially long duration #log_slow_queries = /var/log/mysql/mysql-slow.log #long_query_time = 2 #log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. server-id = 2 replicate-same-server-id = 0 auto-increment-increment = 2 auto-increment-offset = 2 master-host = <SQL1's IP> master-user = slave_user master-password = "slave_password" master-connect-retry = 60 replicate-do-db = db1 log-bin= /var/log/mysql/mysql-bin.log binlog-do-db = db1 binlog-ignore-db = mysql relay-log = /var/lib/mysql/slave-relay.log relay-log-index = /var/lib/mysql/slave-relay-log.index expire_logs_days = 10 max_binlog_size = 500M # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! # # * Security Features # # Read the manual, too, if you want chroot! # chroot = /var/lib/mysql/ # # For generating SSL certificates I recommend the OpenSSL GUI "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 16M # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/

  Read the article

• Linux HA cluster w/Xen, Heartbeat, Pacemaker. domU does not failover to secondary node

  - by Kendall

  I am having the followig problem with an OenSuSE + Heartbeat + Pacemaker + Xen HA cluster: when the node a Xen domU is running on is "dead" the Xen domU running on it is not restarted on the second node. The cluster is setup with two nodes, each running OpenSuSE-11.3, Heartbeat 3.0, and Pacemaker 1.0 in CRM mode. For storage I am using a LUN on an iSCSI SAN device; the LUN is formatted with OCFS2 and managed with LVM. The Xen domU has two logical volumes; one for root and the other for swap. I am using IPMI cards for STONITH devices, and a dedicated ethernet link for heartbeat communications. The ha.cf file is as follows: keepalive 1 deadtime 10 warntime 5 udpport 694 ucast eth1 auto_failback off node dhcp-166 node stage use_logd yes crm yes My resources look as follows: shocrm(live)configure# show node $id="5c1aa924-bba4-4f95-a367-6c9a58ac4a38" dhcp-166 node $id="cebc92eb-af24-4833-aaf0-672adf80b58e" stage primitive Xen-Util ocf:heartbeat:Xen \ meta target-role="Started" \ operations $id="Xen-Util-operations" \ op start interval="0" timeout="60" start-delay="0" \ op stop interval="0" timeout="120" \ params xmfile="/etc/xen/vm/xen-util" primitive my-stonith stonith:external/ipmi \ params hostname="dhcp-166" ipaddr="192.168.3.106" userid="ADMIN" passwd="xxx" \ op monitor interval="2m" timeout="60s" primitive my-stonith2 stonith:external/ipmi \ params hostname="stage" ipaddr="192.168.3.105" userid="ADMIN" passwd="xxx" \ op monitor interval="2m" timeout="60s" property $id="cib-bootstrap-options" \ dc-version="1.0.9-89bd754939df5150de7cd76835f98fe90851b677" \ cluster-infrastructure="Heartbeat" The Xen domU config file is as follows: name = "xen-util" bootloader = "/usr/lib/xen/boot/domUloader.py" #bootargs = "xvda1:/vmlinuz-xen,/initrd-xen" bootargs = "--entry=xvda1:/boot/vmlinuz-xen,/boot/initrd-xen" memory = 4096 disk = [ 'phy:vg_xen/xen-util-root,xvda1,w', 'phy:vg_xen/xen-util-swap,xvda2,w', ] root = "/dev/xvda1" vif = [ 'mac=00:16:3e:42:42:06' ] #vfb = [ 'type=vnc,vncunused=0,vnclisten=192.168.3.172' ] extra = "" Say domU "Xen-Util" is running on node "stage"; if "stage" goes down, "Xen-Util" does not restart on node "dhcp-166". It seems to want to try as an "xm list" will show it for a few seconds and if you "xm console xen-util" it will give a message like "copying /boot/kernel.gz from xvda1 to /var/lib/xen/tmp/kernel.a53gs for booting". However, it never gets past that, eventually gives up, and no longer appears in "xm list". Now, when node "stage" comes back online after being power cycled, it detects that "Xen-Util" isn't running, and starts it (on stage). I've tried starting "Xen-Util" on node "dhcp-166" without the cluster running, and it works fine. No problems. So, I know it works in that respect. Any ideas? Thanks!

  Read the article

• Benchmarking hosting providers IO with Bonnie

  - by Derek Organ

  Ok, because of a bunch of projects I'm working on I've access to dedicated Servers on a 3 hosting providers. As an experiment and for educational purposes I decided to see if I could benchmark how good the IO is with each. Bit of research lead me to Bonnie++ So I installed it on the server and ran this simple command /usr/sbin/bonnie -d /tmp/foo The 3 machines in different hosting providers are all dedicated machines, one is a VPS, other two are on some cloud platform e.g. VMWare / Xen using some kind of clustered SAN for storage This might be a naive thing to do but here are the results I found. HOST A Version 1.03c ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP xxxxxxxxxxxxxxxx 1G 45081 88 56244 14 19167 4 20965 40 67110 6 67.2 0 ------Sequential Create------ --------Random Create-------- -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 15264 28 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ xxxxxxxx,1G,45081,88,56244,14,19167,4,20965,40,67110,6,67.2,0,16,15264,28,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++ HOST B Version 1.03d ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP xxxxxxxxxxxx 4G 43070 91 64510 15 19092 0 29276 47 39169 0 448.2 0 ------Sequential Create------ --------Random Create-------- -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 24799 52 +++++ +++ +++++ +++ 25443 54 +++++ +++ +++++ +++ xxxxxxx,4G,43070,91,64510,15,19092,0,29276,47,39169,0,448.2,0,16,24799,52,+++++,+++,+++++,+++,25443,54,+++++,+++,+++++,+++ HOST C Version 1.03c ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP xxxxxxxxxxxxx 1536M 15598 22 85698 13 258969 20 16194 22 723655 21 +++++ +++ ------Sequential Create------ --------Random Create-------- -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP 16 14142 22 +++++ +++ 18621 22 13544 22 +++++ +++ 17363 21 xxxxxxxx,1536M,15598,22,85698,13,258969,20,16194,22,723655,21,+++++,+++,16,14142,22,+++++,+++,18621,22,13544,22,+++++,+++,17363,21 Ok, so first off what is the best way to read the figures and are there any issues with really comparing these numbers? Is this in any way a true representation of IO Speed? If not is there any way for me to test that? Note: these 3 machines are using either Ubuntu or Debian (I presume that doesn't really matter)

  Read the article

• Xenserver 5.5 U2 a bit unstable with an unstable W2003 VM

  - by twistedbrain

  In the last week I had to reboot the host system twice and the second one by means of the power button. The system is a Dell PE 6950 (4 Opteron dual core, 2,8 Ghz, 16 GB RAM, 900 GB disk in a RAID 10 array composed by 4 450GB 15000 rpm disks) with XenServer 5.5 U2. We're installing it and at now there are working in production a 2003 32 bit Windows server VM with 2 GB RAM, 3 vcpu and about 200 GB disk in 4 partition (12 GB boot, 20 GB program, 80 GB user data, 80 GB other data). The first time I was compressing many Windows 2003 folders (some tens GB by means of W2003 compressed folder option) from a Windows remote console and some hours before my colleague installed Backup Exec agent that was alredy installed and that required a reboot (that was pending). The console stopped responding, it was no more possible to connect by means of remote console or by means of the console of the XenCentre, it was still possible from the network to use the shared folder of the VM and the programs on it (2 db and a GIS program), but the print server didn't work any more and I couldn't give remote reboot from other domain controller hosts. I couldn't stop the virtual machine neither from the XenCentre, neither from the command line of the host also forcing the reboot. I had to reboot the host server. Yesterday it has been worst. I installed a template of another VM, CentOS 5.3 and then, put the DVD in the drive of the host. Then, before the install and after the boot I checked for defect the DVD and the W2003 VM began to respond slowly (I was connected by means of an administration remote console) the task manager showed only mid or low load, it is, only the first of the 3 vcpu was loaded (about 70%), while the other two were about at 20% and also the disk I/O was not so heavy. Then the users were not so happy because they couldn't any more use the MS word docs on the server. I immediately stopped the check of the DVD (to do that I had to force the stop of such Centos 5.3 VM), then some users could again use their docs, but other had still problems, so I decided to reboot the VM, but it doesn't stopped, neither from XenCenter, neither from command line, neither forcing the reboot. Then I tried to reboot of the host, but it didn't worked, neither from the XenCentre, neither from the host prompt (shutdown -r now as root: it told that it was shutting down, but then it didn't did that). So I had to power off by means of the power button of the server (before I tried some Magic SyS REQ, but I saw that Xen isn't compiled with this option enabled). What could you suggest about my problem, what can I look, search and see? In the W2003 VM logs there are no errors or warning to explain what happened. Some more exciting, amusing and inspiring words of poetry (the facts happened around 11 am): \# egrep -i 'err|warning' xensource.log [20100219 10:32:05.597|debug|culo|6301 unix-RPC|VBD.plug R:c81bcda701f6|xenops] watch: watching xenstore paths: [ /xapi/0/frontend/vbd/51712/hotplug; /local/domain/0/backend/vbd/0/51712/tapdisk-error ] with timeout 1200.000000 seconds [20100219 10:32:05.597|debug|culo|6301 unix-RPC|VBD.plug R:c81bcda701f6|xenops] watch: fired on /local/domain/0/backend/vbd/0/51712/tapdisk-error [20100219 10:32:14.314|debug|culo|6335 unix-RPC|VBD.unplug R:9258f54578d6|xenops] watch: watching xenstore paths: [ /local/domain/0/backend/vbd/0/51712/shutdown-done; /local/domain/0/error/device/vbd/51712/error ] with timeout 1200.000000 seconds [20100219 10:32:14.337|debug|culo|6335 unix-RPC|VBD.unplug R:9258f54578d6|xenops] xenstore-rm /local/domain/0/error/backend/vbd/0 [20100219 10:32:14.337|debug|culo|6335 unix-RPC|VBD.unplug R:9258f54578d6|xenops] xenstore-rm /local/domain/0/error/device/vbd/51712 [20100219 10:32:14.338|debug|culo|6335 unix-RPC|VBD.unplug R:9258f54578d6|xenops] watch: fired on /local/domain/0/error/device/vbd/51712/error [20100219 10:53:48.903|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|helpers] Ignoring exception: INTERNAL_ERROR: [ Xb.Noent ] while Vmops.destroy_domain: Destroying domid 14 guest session [20100219 10:53:52.048|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/0/error/backend/tap/14 [20100219 10:53:52.048|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/14/error/device/vbd/51744 [20100219 10:53:52.085|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/0/error/backend/tap/14 [20100219 10:53:52.086|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/14/error/device/vbd/51728 [20100219 10:53:52.122|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/0/error/backend/tap/14 [20100219 10:53:52.122|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/14/error/device/vbd/51712 [20100219 10:53:52.127|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/0/error/backend/vbd/14 [20100219 10:53:52.128|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/14/error/device/vbd/51760 [20100219 10:53:52.496|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] Device.Vif.hard_shutdown about to blow away backend and error paths [20100219 10:53:52.497|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/0/error/backend/vif/14 [20100219 10:53:52.497|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/14/error/device/vif/0 [20100219 10:53:53.385|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] Device.Vif.hard_shutdown about to blow away backend and error paths [20100219 10:53:53.386|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/0/error/backend/vif/14 [20100219 10:53:53.386|debug|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|xenops] xenstore-rm /local/domain/14/error/device/vif/1 [20100219 10:53:53.389| warn|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|hotplug] Warning, deleting 'vif' entry from /xapi/14/hotplug/vif/0 [20100219 10:53:53.391| warn|culo|6418|Async.VM.hard_shutdown R:88d2095678f7|hotplug] Warning, deleting 'vif' entry from /xapi/14/hotplug/vif/1 [20100219 11:20:49.766|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|helpers] Ignoring exception: INTERNAL_ERROR: [ Xb.Noent ] while Vmops.destroy_domain: Destroying domid 11 guest session [20100219 11:20:50.339|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/0/error/backend/tap/11 [20100219 11:20:50.339|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/11/error/device/vbd/832 [20100219 11:20:50.360|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/0/error/backend/tap/11 [20100219 11:20:50.360|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/11/error/device/vbd/768 [20100219 11:20:50.366|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/0/error/backend/vbd/11 [20100219 11:20:50.366|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/11/error/device/vbd/5696 [20100219 11:20:50.753|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] Device.Vif.hard_shutdown about to blow away backend and error paths [20100219 11:20:50.754|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/0/error/backend/vif/11 [20100219 11:20:50.754|debug|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|xenops] xenstore-rm /local/domain/11/error/device/vif/1 [20100219 11:20:50.757| warn|culo|6484|Async.VM.clean_shutdown R:78d3c3e28cb6|hotplug] Warning, deleting 'vif' entry from /xapi/11/hotplug/vif/1 [20100219 11:28:13.803|debug|culo|6610 inet-RPC|Connection to VM console R:e9f8b76e8975|console] error: INTERNAL_ERROR: [ Unix.Unix_error(63, "connect", "") ]

  Read the article

• EC2 instance suddenly refusing SSH connections and won't respond to ping

  - by Chris

  My instance was running fine and this morning I was able to access a Ruby on Rails app hosted on it. An hour later I suddenly wasn't able to access my site, my SSH connection attempts were refused and the server wasn't even responding to ping. I didn't change anything on my system during that hour and reboots aren't fixing it. I've never had any problems connecting or pinging the system before. Can someone please help? This is on my production system! OS: CentOS 5 AMI ID: ami-10b55379 Type: m1.small [] ~% ssh -v *****@meeteor.com OpenSSH_5.2p1, OpenSSL 0.9.8l 5 Nov 2009 debug1: Reading configuration data /etc/ssh_config debug1: Connecting to meeteor.com [184.73.235.191] port 22. debug1: connect to address 184.73.235.191 port 22: Connection refused ssh: connect to host meeteor.com port 22: Connection refused [] ~% ping meeteor.com PING meeteor.com (184.73.235.191): 56 data bytes Request timeout for icmp_seq 0 Request timeout for icmp_seq 1 Request timeout for icmp_seq 2 ^C --- meeteor.com ping statistics --- 4 packets transmitted, 0 packets received, 100.0% packet loss [] ~% ========= System Log ========= Restarting system. Linux version 2.6.16-xenU ([email protected]) (gcc version 4.0.1 20050727 (Red Hat 4.0.1-5)) #1 SMP Mon May 28 03:41:49 SAST 2007 BIOS-provided physical RAM map: Xen: 0000000000000000 - 000000006a400000 (usable) 980MB HIGHMEM available. 727MB LOWMEM available. NX (Execute Disable) protection: active IRQ lockup detection disabled Built 1 zonelists Kernel command line: root=/dev/sda1 ro 4 Enabling fast FPU save and restore... done. Enabling unmasked SIMD FPU exception support... done. Initializing CPU#0 PID hash table entries: 4096 (order: 12, 65536 bytes) Xen reported: 2599.998 MHz processor. Dentry cache hash table entries: 131072 (order: 7, 524288 bytes) Inode-cache hash table entries: 65536 (order: 6, 262144 bytes) Software IO TLB disabled vmalloc area: ee000000-f53fe000, maxmem 2d7fe000 Memory: 1718700k/1748992k available (1958k kernel code, 20948k reserved, 620k data, 144k init, 1003528k highmem) Checking if this processor honours the WP bit even in supervisor mode... Ok. Calibrating delay using timer specific routine.. 5202.30 BogoMIPS (lpj=26011526) Mount-cache hash table entries: 512 CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line) CPU: L2 Cache: 1024K (64 bytes/line) Checking 'hlt' instruction... OK. Brought up 1 CPUs migration_cost=0 Grant table initialized NET: Registered protocol family 16 Brought up 1 CPUs xen_mem: Initialising balloon driver. highmem bounce pool size: 64 pages VFS: Disk quotas dquot_6.5.1 Dquot-cache hash table entries: 1024 (order 0, 4096 bytes) Initializing Cryptographic API io scheduler noop registered io scheduler anticipatory registered (default) io scheduler deadline registered io scheduler cfq registered i8042.c: No controller found. RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize Xen virtual console successfully installed as tty1 Event-channel device installed. netfront: Initialising virtual ethernet driver. mice: PS/2 mouse device common for all mice md: md driver 0.90.3 MAX_MD_DEVS=256, MD_SB_DISKS=27 md: bitmap version 4.39 NET: Registered protocol family 2 Registering block device major 8 IP route cache hash table entries: 65536 (order: 6, 262144 bytes) TCP established hash table entries: 262144 (order: 9, 2097152 bytes) TCP bind hash table entries: 65536 (order: 7, 524288 bytes) TCP: Hash tables configured (established 262144 bind 65536) TCP reno registered TCP bic registered NET: Registered protocol family 1 NET: Registered protocol family 17 NET: Registered protocol family 15 Using IPI No-Shortcut mode md: Autodetecting RAID arrays. md: autorun ... md: ... autorun DONE. kjournald starting. Commit interval 5 seconds EXT3-fs: mounted filesystem with ordered data mode. VFS: Mounted root (ext3 filesystem) readonly. Freeing unused kernel memory: 144k freed *************************************************************** *************************************************************** ** WARNING: Currently emulating unsupported memory accesses ** ** in /lib/tls glibc libraries. The emulation is ** ** slow. To ensure full performance you should ** ** install a 'xen-friendly' (nosegneg) version of ** ** the library, or disable tls support by executing ** ** the following as root: ** ** mv /lib/tls /lib/tls.disabled ** ** Offending process: init (pid=1) ** *************************************************************** *************************************************************** Pausing... 5Pausing... 4Pausing... 3Pausing... 2Pausing... 1Continuing... INIT: version 2.86 booting Welcome to CentOS release 5.4 (Final) Press 'I' to enter interactive startup. Setting clock : Fri Oct 1 14:35:26 EDT 2010 [ OK ] Starting udev: [ OK ] Setting hostname localhost.localdomain: [ OK ] No devices found Setting up Logical Volume Management: [ OK ] Checking filesystems Checking all file systems. [/sbin/fsck.ext3 (1) -- /] fsck.ext3 -a /dev/sda1 /dev/sda1: clean, 275424/1310720 files, 1161123/2621440 blocks [ OK ] Remounting root filesystem in read-write mode: [ OK ] Mounting local filesystems: [ OK ] Enabling local filesystem quotas: [ OK ] Enabling /etc/fstab swaps: [ OK ] INIT: Entering runlevel: 4 Entering non-interactive startup Starting background readahead: [ OK ] Applying ip6tables firewall rules: modprobe: FATAL: Module ip6_tables not found. ip6tables-restore v1.3.5: ip6tables-restore: unable to initializetable 'filter' Error occurred at line: 3 Try `ip6tables-restore -h' or 'ip6tables-restore --help' for more information. [FAILED] Applying iptables firewall rules: [ OK ] Loading additional iptables modules: ip_conntrack_netbios_ns [ OK ] Bringing up loopback interface: [ OK ] Bringing up interface eth0: Determining IP information for eth0... done. [ OK ] Starting auditd: [FAILED] Starting irqbalance: [ OK ] Starting portmap: [ OK ] FATAL: Module lockd not found. Starting NFS statd: [ OK ] Starting RPC idmapd: FATAL: Module sunrpc not found. FATAL: Error running install command for sunrpc Error: RPC MTAB does not exist. Starting system message bus: [ OK ] Starting Bluetooth services:[ OK ] [ OK ] Can't open RFCOMM control socket: Address family not supported by protocol Mounting other filesystems: [ OK ] Starting PC/SC smart card daemon (pcscd): [ OK ] Starting hidd: Can't open HIDP control socket: Address family not supported by protocol [FAILED] Starting autofs: Starting automount: automount: test mount forbidden or incorrect kernel protocol version, kernel protocol version 5.00 or above required. [FAILED] [FAILED] Starting sshd: [ OK ] Starting cups: [ OK ] Starting sendmail: [ OK ] Starting sm-client: [ OK ] Starting console mouse services: no console device found[FAILED] Starting crond: [ OK ] Starting xfs: [ OK ] Starting anacron: [ OK ] Starting atd: [ OK ] % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 390 100 390 0 0 58130 0 --:--:-- --:--:-- --:--:-- 58130 100 390 100 390 0 0 56984 0 --:--:-- --:--:-- --:--:-- 0 Starting yum-updatesd: [ OK ] Starting Avahi daemon... [ OK ] Starting HAL daemon: [ OK ] Starting OSSEC: [ OK ] Starting smartd: [ OK ] c CentOS release 5.4 (Final) Kernel 2.6.16-xenU on an i686 domU-12-31-39-00-C4-97 login: INIT: Id "2" respawning too fast: disabled for 5 minutes INIT: Id "3" respawning too fast: disabled for 5 minutes INIT: Id "4" respawning too fast: disabled for 5 minutes INIT: Id "5" respawning too fast: disabled for 5 minutes INIT: Id "6" respawning too fast: disabled for 5 minutes

  Read the article

• mobile broadband recommendations for Lenovo T500

  - by Justin Grant

  I use a Lenovo T500 primarily in and around San Francisco, although I do some travel in the US on business and occasionally to Europe/Asia. I'm looking for a good mobile broadband option for my T500. I am admittedly baffled by the various mobile-broadband choices (3G vs. 4G, WiMax vs. LTE vs. MIMO vs. ..., etc.). My priorities are (in this order): Compatible with Lenovo T500 and Windows 7. I realize only the AT&T accessory card is listed on Lenovo's site, but I've also heard that other cards will work in my T500 too, like the WiMax/Wifi combo card-- so I'm interested in what actually works, not necessarily only what Lenovo is promoting. Reliable coverage in US large cities, especially the SF Bay Area. my IPhone has lousy coverage in many spots, so I'd be nervous about an AT&T 3G option unless the problem is with the IPhone and not AT&T's network. I'm OK with non-great coverage outside major US cities, since I don't do much travel in those areas. Speed. faster is better. Internal card. I'd slightly prefer something I could install inside my T500 instead of a dongle on the side that might break off, although this is my lowest priority so it's not a big deal. Price. I don't want to pay over $100/month. I've tried lots of Googling and haven't come up with clear answers. I've seen lots of general overviews without recommendations, and lots of passionate opinions which don't feel objective (and don't help me understand compatibility with my hardware & geography). Can you recommend a good, objective guide online, ideally for Lenovo although general guide is OK too, which can help me figure out which option is the best one for me? I'd also be interested in your own personal experiences of using mobile broadband using a Lenovo T500. I'll accept the answer which gets me closest to making a decision.

  Read the article

• Why are my hard drives failing?

  - by WishCow

  I have a small Ubuntu server running at home, with 2 HDDs. There are two software raids (raid1) on the disks, managed by mdadm, which I believe is irrelevant, but mentioning it anyway. Both of the HDDs are Western Digital, and have been used for around 2 years, when one of them started making clicking noises, and died. I figured that maybe it's natural after 2 years, so I bought a new one, and resynced the raid arrays. After about a month, the other drive also died. I didn't get suspicious, since both drives have been bought at the same time, it's not that surprising to see both of them near each other, so I bought another one. So far, 2 old drives failed, and 2 brand new in the system. After one month, one of the new drives died. This is when it started getting suspicious. Since the PC was put together from some really old parts (think AthlonXP), I figured that maybe the motherboard's SATA controller is the culprit. Of course you can't switch parts easily in an old PC like this, so I bought a whole system, new MB, new CPU, new RAM. Took the just failed drive back, since it was under warranty, and got it replaced. So it is up to 2 failed drives from the old ones, and 1 failed drive from the new ones. No problems, for 1 month. After that errors were creeping up again in /var/log/messages, and mdadm was reporting raid array failures. I started tearing my hair out. Everything is new in the system, it's up to the third brand new HDD, it's simply not possible that all of the new drives that I bought were faulty. Let's see what is still common... the cables. Okay, long shot, let's replace the SATA cables. Take HDD back, smile to the guy at the counter and say that I'm really unlucky. He replaces the HDD. I come home, one month passes and one of HDDs fails, again. I'm not joking. Two of the brand new HDDs have failed. Maybe it's a bug in the OS. Let's see what the manufacturer's testing tool says. Download testing tool, burn it to a CD, reboot, leave HDD testing overnight. Test says that the drive is faulty, and I should back up everything, if I still can. I don't know what's happening, but it does not look like a software problem, something is definitely thrashing the HDDs. I should mention now, that the whole system is in a shoebox. Since there are a load of "build your own ikea case" stuff, I thought there shouldn't be any problems throwing the thing in a box, and stuffing it away somewhere. The box is well ventilated, but I thought that just maybe the drives were overheating. There is no other possible answer to this. So I took the HDD back, and got it replaced (for the 3rd time), and bought HDD coolers. And just now, I have heard the sound of doom. click click whizzzzzzzzz. SSH into the box: You have new mail! mail r 1 DegradedArrayEvent on /dev/md0 ... dmesg output: [47128.000051] ata3: lost interrupt (Status 0x50) [47128.000097] end_request: I/O error, dev sda, sector 58588863 [47128.000134] md: super_written gets error=-5, uptodate=0 [48043.976054] ata3: lost interrupt (Status 0x50) [48043.976086] ata3.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen [48043.976132] ata3.00: cmd c8/00:18:bf:40:52/00:00:00:00:00/e1 tag 0 dma 12288 in [48043.976135] res 40/00:00:00:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout) [48043.976208] ata3.00: status: { DRDY } [48043.976241] ata3: soft resetting link [48044.148446] ata3.00: configured for UDMA/133 [48044.148457] ata3.00: device reported invalid CHS sector 0 [48044.148477] ata3: EH complete Recap: No possibility of overheating 6 drives have failed, 4 of those have been brand new. I'm not sure now that the original two have been faulty, or suffered the same thing that the new ones. There is nothing common in the system, apart from the OS which is Ubuntu Karmic now (started with Jaunty). New MB, new CPU, new RAM, new SATA cables. No, the little holes on the HDD are not covered I'm crying. Really. I don't have the face to return to the store now, it's not possible for 4 drives to fail under 4 months. A few ideas that I have been thinking: Is it possible that I fuck up something when I partition and resync the drives? Can it be so bad that it physicaly wrecks the drive? (since the vendor supplied tool says that the drive is damaged) I do the partitoning with fdisk, and use the same block size for the raid1 partitions (I check the exact block sizes with fdisk -lu) Is it possible that the linux kernel or mdadm, or something is not compatible with this exact brand of HDDs, and thrashes them? Is it possible that it may be the shoebox? Try placing it somewhere else? It's under a shelf now, so humidity is not a problem either. Is it possible that a normal PC case will solve my problem (I'm going to shoot myself then)? I will get a picture tomorrow. Am I just simply cursed? Any help or speculation is greatly appreciated. Edit: The power strip is guarded against overvoltage. Edit2: I have moved inbetween these 4 months, so the possibility of the cause being "dirty" electricity in both places, is very low. Edit3: I have checked the voltages in the BIOS (couldn't borrow a multimeter), and they are all seem correct, the biggest discrepancy is in the 12V, because it's supplying 11.3. Should I be worried about that? Edit4: I put my desktop PC's PSU into the server. The BIOS reported much more accurate voltage readings, and also it has successfully rebuilt the raid1 array, which took some 3-4 hours, so I feel a little positive now. Will get a new PSU tomorrow to test with that. Also, attaching the picture about the box: (disregard the 3rd drive)

  Read the article

• Optimize php-fpm and varnish for a powerfull server

  - by Jim

  My setup is: Intel® Core™ i7-2600 and RAM 16 GB DDR3 RAM varnish+nginx+php-fpm+apc for a not very heavy WordPress blog with W3 Total Cache and CDN My problem is that after 55 hits per second according to blitz.io varnish starts giving out timeouts. CPU usage at this time is hardly 1%. Free memory at all time remains 10GB+. I tried benchmarking php-fpm directly with result of 150hits/s without any timeouts. But after that the CPU usage goes 100% and it stops responding. Can you help me optimize it to handle more? As i understand nginx has nothing to do over here so i dont put its config. php-fpm config listen = /tmp/php5-fpm.sock listen.allowed_clients = 127.0.0.1 user = nginx group = nginx pm = dynamic pm.max_children = 150 pm.start_servers = 7 pm.min_spare_servers = 2 pm.max_spare_servers = 15 pm.max_requests = 500 slowlog = /var/log/php-fpm/www-slow.log php_admin_value[error_log] = /var/log/php-fpm/www-error.log php_admin_flag[log_errors] = on apc extension = apc.so apc.enabled=1 apc.shm_size=512MB apc.num_files_hint=0 apc.user_entries_hint=0 apc.ttl=7200 apc.use_request_time=1 apc.user_ttl=7200 apc.gc_ttl=3600 apc.cache_by_default=1 apc.filters apc.mmap_file_mask=/tmp/apc.XXXXXX apc.file_update_protection=2 apc.enable_cli=0 apc.max_file_size=1M apc.stat=1 apc.stat_ctime=0 apc.canonicalize=0 apc.write_lock=1 apc.report_autofilter=0 apc.rfc1867=0 apc.rfc1867_prefix =upload_ apc.rfc1867_name=APC_UPLOAD_PROGRESS apc.rfc1867_freq=0 apc.rfc1867_ttl=3600 apc.include_once_override=0 apc.lazy_classes=0 apc.lazy_functions=0 apc.coredump_unmap=0 apc.file_md5=0 apc.preload_path Varnish VCL backend default { .host = "127.0.0.1"; .port = "8080"; .connect_timeout = 6s; .first_byte_timeout = 6s; .between_bytes_timeout = 60s; } acl purgehosts { "localhost"; "127.0.0.1"; } # Called after a document has been successfully retrieved from the backend. sub vcl_fetch { # Uncomment to make the default cache "time to live" is 5 minutes, handy # but it may cache stale pages unless purged. (TODO) # By default Varnish will use the headers sent to it by Apache (the backend server) # to figure out the correct TTL. # WP Super Cache sends a TTL of 3 seconds, set in wp-content/cache/.htaccess set beresp.ttl = 24h; # Strip cookies for static files and set a long cache expiry time. if (req.url ~ "\.(jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|pdf|txt|tar|wav|bmp|rtf|js|flv|swf|html|htm)$") { unset beresp.http.set-cookie; set beresp.ttl = 24h; } # If WordPress cookies found then page is not cacheable if (req.http.Cookie ~"(wp-postpass|wordpress_logged_in|comment_author_)") { # set beresp.cacheable = false;#versions less than 3 #beresp.ttl>0 is cacheable so 0 will not be cached set beresp.ttl = 0s; } else { #set beresp.cacheable = true; set beresp.ttl=24h;#cache for 24hrs } # Varnish determined the object was not cacheable #if ttl is not > 0 seconds then it is cachebale if (!beresp.ttl > 0s) { # set beresp.http.X-Cacheable = "NO:Not Cacheable"; } else if ( req.http.Cookie ~"(wp-postpass|wordpress_logged_in|comment_author_)" ) { # You don't wish to cache content for logged in users set beresp.http.X-Cacheable = "NO:Got Session"; return(hit_for_pass); #previously just pass but changed in v3+ } else if ( beresp.http.Cache-Control ~ "private") { # You are respecting the Cache-Control=private header from the backend set beresp.http.X-Cacheable = "NO:Cache-Control=private"; return(hit_for_pass); } else if ( beresp.ttl < 1s ) { # You are extending the lifetime of the object artificially set beresp.ttl = 300s; set beresp.grace = 300s; set beresp.http.X-Cacheable = "YES:Forced"; } else { # Varnish determined the object was cacheable set beresp.http.X-Cacheable = "YES"; if (beresp.status == 404 || beresp.status >= 500) { set beresp.ttl = 0s; } # Deliver the content return(deliver); } sub vcl_hash { # Each cached page has to be identified by a key that unlocks it. # Add the browser cookie only if a WordPress cookie found. if ( req.http.Cookie ~"(wp-postpass|wordpress_logged_in|comment_author_)" ) { #set req.hash += req.http.Cookie; hash_data(req.http.Cookie); } } # vcl_recv is called whenever a request is received sub vcl_recv { # remove ?ver=xxxxx strings from urls so css and js files are cached. # Watch out when upgrading WordPress, need to restart Varnish or flush cache. set req.url = regsub(req.url, "\?ver=.*$", ""); # Remove "replytocom" from requests to make caching better. set req.url = regsub(req.url, "\?replytocom=.*$", ""); remove req.http.X-Forwarded-For; set req.http.X-Forwarded-For = client.ip; # Exclude this site because it breaks if cached if ( req.http.host == "sr.ituts.gr" ) { return( pass ); } # Serve objects up to 2 minutes past their expiry if the backend is slow to respond. set req.grace = 120s; # Strip cookies for static files: if (req.url ~ "\.(jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|pdf|txt|tar|wav|bmp|rtf|js|flv|swf|html|htm)$") { unset req.http.Cookie; return(lookup); } # Remove has_js and Google Analytics __* cookies. set req.http.Cookie = regsuball(req.http.Cookie, "(^|;\s*)(__[a-z]+|has_js)=[^;]*", ""); # Remove a ";" prefix, if present. set req.http.Cookie = regsub(req.http.Cookie, "^;\s*", ""); # Remove empty cookies. if (req.http.Cookie ~ "^\s*$") { unset req.http.Cookie; } if (req.request == "PURGE") { if (!client.ip ~ purgehosts) { error 405 "Not allowed."; } #previous version ban() was purge() ban("req.url ~ " + req.url + " && req.http.host == " + req.http.host); error 200 "Purged."; } # Pass anything other than GET and HEAD directly. if (req.request != "GET" && req.request != "HEAD") { return( pass ); } /* We only deal with GET and HEAD by default */ # remove cookies for comments cookie to make caching better. set req.http.cookie = regsub(req.http.cookie, "1231111111111111122222222333333=[^;]+(; )?", ""); # never cache the admin pages, or the server-status page, or your feed? you may want to..i don't if (req.request == "GET" && (req.url ~ "(wp-admin|bb-admin|server-status|feed)")) { return(pipe); } # don't cache authenticated sessions if (req.http.Cookie && req.http.Cookie ~ "(wordpress_|PHPSESSID)") { return(lookup); } # don't cache ajax requests if(req.http.X-Requested-With == "XMLHttpRequest" || req.url ~ "nocache" || req.url ~ "(control.php|wp-comments-post.php|wp-login.php|bb-login.php|bb-reset-password.php|register.php)") { return (pass); } return( lookup ); } Varnish Daemon options DAEMON_OPTS="-a :80 \ -T 127.0.0.1:6082 \ -f /etc/varnish/ituts.vcl \ -u varnish -g varnish \ -S /etc/varnish/secret \ -p thread_pool_add_delay=2 \ -p thread_pools=8 \ -p thread_pool_min=100 \ -p thread_pool_max=1000 \ -p session_linger=50 \ -p session_max=150000 \ -p sess_workspace=262144 \ -s malloc,5G" Im not sure where to start, should i for start optimize php-fpm and then go to varnish or php-fpm is at its max right now so i should start looking for the problem in varnish?

  Read the article

• How do you backup 40+ Centos5.5 servers?

  - by John Little

  We are embarrassed to ask this question. Apologies for our lack of UNIX expertise. We have inherited 40+ centos 5.5 servers, and don't know how to back them up. We need low level clone type images so that we could restore the servers from scratch if we had to replace the HDs etc. We have used the "dd" command, but we assume this only works if you want to back up one local disk to another, not 40 servers to one server with an external USB HD attached. All 40 servers have a pair of mirrored disks (dont know if its HW or SW raid). Most only have 100MB used. SErvers are running apache, zend, tomcat, mysql etc. Ideally we dont want to have to shut them down to backup (but could). We assume that standard unix commands like tar, cpio, rsync, scp etc. are of no use as they only copy files, not partitions, all attributes, groups etc. i.e. do not produce a result which can simply be re-imaged to a new HD to get the serer back from dead. We have a large SAN, a spare windows box and spare unix boxes, but these are only visible to one layer in the network. We have an unused Dell DL2000 monster tape unit, but no sw or documentation for it. WE have a copy of symantec backup exec, but we have no budget for unix client licenses. (The company has negative amounts of money). We need to be able to initiate the backup remotely, as we can only access the servers in person in an emergency (i.e. to restore) Googling returns some applications to do this, e.g. clonezilla - looks difficult to install and invasive. Mondo, only seems to support backup if you are local to the machine. Amanda might be an option, but looks like days/weeks of work to learn and setup? Is there anything built into Centos, or do we have to go the route of installing, learning and configuring a set of backup softwares? Any ideas? This must be a pretty standard problem which goggling doesnt give an obvious answer.

  Read the article

• How to improve Varnish performance?

  - by Darkseal

  We're experiencing a strange problem with our current Varnish configuration. 4x Web Servers (IIS 6.5 on Windows 2003 Server, each installed on a Intel(R) Xeon(R) CPU E5450 @ 3.00GHz Quad Core, 4GB RAM) 3x Varnish Servers (varnish-3.0.3 revision 9e6a70f on Ubuntu 12.04.2 LTS - 64 bit/precise, Kernel Linux 3.2.0-29-generic, each installed on a Intel(R) Xeon(R) CPU E5450 @ 3.00GHz Quad Core, 4GB RAM) The Varnish Servers performance are awfully bad in general, to the point that if we shut down one of them the other two are unable to fullfill all the requests and start to skip beats resulting in pending requests, timeouts, 404, etc. What can we do to improve our Varnish performance? Considering that we're getting less than 5k request per seconds during our max peak, we should be able to serve our pages even with a single one of them without any problem. We use a standard, vanilla CFG, as shown by this varnishadm param.show output: acceptor_sleep_decay 0.900000 [] acceptor_sleep_incr 0.001000 [s] acceptor_sleep_max 0.050000 [s] auto_restart on [bool] ban_dups on [bool] ban_lurker_sleep 0.010000 [s] between_bytes_timeout 60.000000 [s] cc_command "exec gcc -std=gnu99 -g -O2 -pthread -fpic -shared - Wl,-x -o %o %s" cli_buffer 8192 [bytes] cli_timeout 20 [seconds] clock_skew 10 [s] connect_timeout 0.700000 [s] critbit_cooloff 180.000000 [s] default_grace 10.000000 [seconds] default_keep 0.000000 [seconds] default_ttl 120.000000 [seconds] diag_bitmap 0x0 [bitmap] esi_syntax 0 [bitmap] expiry_sleep 1.000000 [seconds] fetch_chunksize 128 [kilobytes] fetch_maxchunksize 262144 [kilobytes] first_byte_timeout 60.000000 [s] group varnish (113) gzip_level 6 [] gzip_memlevel 8 [] gzip_stack_buffer 32768 [Bytes] gzip_tmp_space 0 [] gzip_window 15 [] http_gzip_support off [bool] http_max_hdr 64 [header lines] http_range_support on [bool] http_req_hdr_len 8192 [bytes] http_req_size 32768 [bytes] http_resp_hdr_len 8192 [bytes] http_resp_size 32768 [bytes] idle_send_timeout 60 [seconds] listen_address :80 listen_depth 1024 [connections] log_hashstring on [bool] log_local_address off [bool] lru_interval 2 [seconds] max_esi_depth 5 [levels] max_restarts 4 [restarts] nuke_limit 50 [allocations] pcre_match_limit 10000 [] pcre_match_limit_recursion 10000 [] ping_interval 3 [seconds] pipe_timeout 60 [seconds] prefer_ipv6 off [bool] queue_max 100 [%] rush_exponent 3 [requests per request] saintmode_threshold 10 [objects] send_timeout 600 [seconds] sess_timeout 5 [seconds] sess_workspace 16384 [bytes] session_linger 50 [ms] session_max 100000 [sessions] shm_reclen 255 [bytes] shm_workspace 8192 [bytes] shortlived 10.000000 [s] syslog_cli_traffic on [bool] thread_pool_add_delay 2 [milliseconds] thread_pool_add_threshold 2 [requests] thread_pool_fail_delay 200 [milliseconds] thread_pool_max 2000 [threads] thread_pool_min 5 [threads] thread_pool_purge_delay 1000 [milliseconds] thread_pool_stack unlimited [bytes] thread_pool_timeout 300 [seconds] thread_pool_workspace 65536 [bytes] thread_pools 2 [pools] thread_stats_rate 10 [requests] user varnish (106) vcc_err_unref on [bool] vcl_dir /etc/varnish vcl_trace off [bool] vmod_dir /usr/lib/varnish/vmods waiter default (epoll, poll) This is our default.vcl file: LINK sub vcl_recv { # BASIC recv COMMANDS: # # lookup -> search the item in the cache # pass -> always serve a fresh item (no-caching) # pipe -> like pass but ensures a direct-connection with the backend (no-cache AND no-proxy) # Allow the backend to serve up stale content if it is responding slow. # This defines when Varnish should use a stale object if it has one in the cache. set req.grace = 30s; if (client.ip == "127.0.0.1") { # request from NGINX - do not alter X-Forwarded-For set req.http.HTTPS = "on"; } else { # Add an X-Forwarded-For to keep track of original request unset req.http.HTTPS; unset req.http.X-Forwarded-For; set req.http.X-Forwarded-For = client.ip; } set req.backend = www_director; # Strip all cookies to force an anonymous request when the back-end servers are down. if (!req.backend.healthy) { unset req.http.Cookie; } ## HHTP Accept-Encoding if (req.http.Accept-Encoding) { if (req.http.Accept-Encoding ~ "gzip") { set req.http.Accept-Encoding = "gzip"; } else if (req.http.Accept-Encoding ~ "deflate") { set req.http.Accept-Encoding = "deflate"; } else { unset req.http.Accept-Encoding; } } if (req.request != "GET" && req.request != "HEAD" && req.request != "PUT" && req.request != "POST" && req.request != "TRACE" && req.request != "OPTIONS" && req.request != "DELETE") { /* non-RFC2616 or CONNECT */ return (pipe); } if (req.request != "GET" && req.request != "HEAD") { /* only deal with GET and HEAD by default */ return (pass); } if (req.http.Authorization) { return (pass); } if (req.http.HTTPS ~ "on") { return (pass); } ###################################################### # COOKIE HANDLING ###################################################### # METHOD 1: do not remove cookies, but pass the page if they contain TB_NC if (!(req.url ~ "(?i)\.(png|gif|ipeg|jpg|ico|swf|css|js)(\?[a-z0-9]+)?$")) { if (req.http.Cookie && req.http.Cookie ~ "TB_NC") { return (pass); } } return (lookup); } # Code determining what to do when serving items from the IIS Server sub vcl_fetch { unset beresp.http.Server; set beresp.http.Server = "Server-1"; # Allow items to be stale if needed. This is the maximum time Varnish should keep an object. set beresp.grace = 1h; if (req.url ~ "(?i)\.(png|gif|ipeg|jpg|ico|swf|css|js)(\?[a-z0-9]+)?$") { unset beresp.http.set-cookie; } # Default Varnish VCL logic if (!beresp.cacheable || beresp.ttl <= 0s || beresp.http.Set-Cookie || beresp.http.Vary == "*") { set beresp.ttl = 120 s; return(hit_for_pass); } # Not Cacheable if it has specific TB_NC no-caching cookie if (req.http.Cookie && req.http.Cookie ~ "TB_NC") { set beresp.http.X-Cacheable = "NO:Got Cookie"; set beresp.ttl = 120 s; return(hit_for_pass); } # Not Cacheable if it has Cache-Control private else if (beresp.http.Cache-Control ~ "private") { set beresp.http.X-Cacheable = "NO:Cache-Control=private"; set beresp.ttl = 120 s; return(hit_for_pass); } # Not Cacheable if it has Cache-Control no-cache or Pragma no-cache else if (beresp.http.Cache-Control ~ "no-cache" || beresp.http.Pragma ~ "no-cache") { set beresp.http.X-Cacheable = "NO:Cache-Control=no-cache (or pragma no-cache)"; set beresp.ttl = 120 s; return(hit_for_pass); } # If we reach to this point, the object is cacheable. # Cacheable but with not enough ttl: we need to extend the lifetime of the object artificially # NOTE: Varnish default TTL is set in /etc/sysconfig/varnish # and can be checked using the following command: # varnishadm param.show default_ttl else if (beresp.ttl < 1s) { set beresp.ttl = 5s; set beresp.grace = 5s; set beresp.http.X-Cacheable = "YES:FORCED"; } # Cacheable and with valid TTL. else { set beresp.http.X-Cacheable = "YES"; } # DEBUG INFO (Cookies) # set beresp.http.X-Cookie-Debug = "Request cookie: " + req.http.Cookie; return(deliver); } sub vcl_error { set obj.http.Content-Type = "text/html; charset=utf-8"; if (obj.status == 404) { synthetic {" <!-- Markup for the 404 page goes here --> "}; } else if (obj.status == 500) { synthetic {" <!-- Markup for the 500 page goes here --> "}; } else if (obj.status == 503) { if (req.restarts < 4) { return(restart); } else { synthetic {" <!-- Markup for the 503 page goes here --> "}; } } else { synthetic {" <!-- Markup for a generic error page goes here --> "}; } } sub vcl_deliver { if (obj.hits > 0) { set resp.http.X-Cache = "HIT"; } else { set resp.http.X-Cache = "MISS"; } } Thanks in advance,

  Read the article

• Easily use google maps, openstreet maps etc offline.

  - by samkea

  I did it and i am going to explain step by step. The explanatination may appear long but its simple if you follow. Note: All the softwares i have used are the latest and i have packaged them and provided them in the link below. I use Nokia N96 1) RootSign smartComGPS and install it on your phone(i havent provided the signer so that u wuld do some little work. i used Secman' rootsign). 2) Install Universal Maps Downloader, SmartCom OGF2 converter and OziExplorer 3.95.4s on my PC. a) UMD is used to download map tiles from any map source like googlemaps,opensourcemaps etc... and also combine the tiles into an image file like png,jpg,bmp etc... b) SmartCom OGF2 converter is used to convert the image file into a format usable on your mobile phone. c) OziExplorer will help you to calibrate the usable map file so that it can be used with GPS on your mobile phone without the use of internet. 3) Go to google maps or where u pick your maps and pan to the area of your interest. Zoom the map to at least 15 or 16 zoom level where you can see your area clearly and the streets. 4) copy this script in a notepad file and save it on your desktop: javascript:void(prompt('',gApplication.getMap().ge tCenter())); 5) Open the universal maps downloader. You will notice that you are required to add the: left longitude, right longitude,top latitude, bottom latitude. 6) On your map in google maps, doubleclick on the your prefered to most middle point. you will notice that the map will center in that area. 7) copy the script and paste it in the address bar then press enter. You will notice that a dialog with your (top latitude) and longitude respectively pops up. 8) copy the top latitude ONLY and paste it in the corresponding textbox in the UMD. 9) repeat steps 6-7 for the botton latitude. 10)repeat steps 6-7 for left longitude and right longitude too, but u have to copy the longitudes here. (***BTW record these points in the text file as they may be needed later in calibration) 11) Give the zoom level to the same zoom level that you prefered in google maps. 12) Dont forget to choose a path to save your files and under options set the proxy connection settings in UMD if you are using so. 13) Click on start and bingo! there you have your image tiles and a file with an extension .umd will be saved in the same folder. 14) On the UMD, go to tools, click on MapViewer and choose the .umd file. you will now see your map in one piece....and you will smile! 15) Still go to tools and click on map combiner. A dialog will popup for you to choose the .umd file and to enter the IMAGE file name. u can use another extension for the image file like png, jpg etc...i usually use png. 16) Combine.....bingo! there u go! u have an IMAGE file for your map. *I SUGGEST THAT CREATE A .BMP FILE and A .PNG file* 17) Close UMD and open SmartCom OGF2 converter. 18) Choose your .png image and create an ogf2 file. 19) Connect your phone to your PC in Mass Memory mode and transfer the file to the smartComGPS\Maps folder. 20) Now disconnect your phone and load smartComGPS. it will load the map and propt you to add a calibration point. Go ahead and add one calibration point with dummy coordinates. You will notice that it will add another file with extension .map in the smartComGPS\Maps folder. 21) Connect yiur ohone and copy that file and paste it in your working folder on your PC. Delete that .map file from the phone too because you are going to edit it from your PC and put it back. 22) Now Open the OziExplorer, go to file-->Load and Calibrate Map Image. 23) Choose the .bmp image and bingo! it will load with your map in the same zoom level. 24) Now you are going to calibrate. Use the MapView window and take the small box locater to all the 4 cornners of the map. You will notice that the map in the back ground moves to that area too. 25)On the right side, select the Point1 tab. Now you are in calibration mode. Now move the red box in mapview in the left upper corner to calibrate point1. 26) out of mapview go to the the left upper corner of the background map and choose poit (0,0) and your 1st calibration point. You will notice that these X,Y cordinated will be reflected in the Point1 image cordinates. 27) now go back to the text file where you saved your coordibates and enter the top latitude and the left longitude in the corresponding places. 28) Repeat steps 25-27 for point2,point3,point4 and click on save. Thats it, you have calibrated your image and you are about to finish. 29) Go to save and a dilaog which prompts you to save a .map file will poop up. Do save the map file in your working folder. 30) Right click that .map file and edit the filename in the .map file to remove the pc's directory structure. Eg. Change C\OziExplorer\data\Kampala.bmp to Kampala.ogf2. 31) Save the .map file in the smartComGPS\Maps folder on your phone. 32) now open smartComGPS on your phone and bingo! there is your map with GPS capability and in the same zoom level. 33) In smartComGPS options, choose connect and simulate. By now you should be smiling. Whoa! Hope i was of help. i case you get a problem, please inform me Below is the link to the software. regards. http://rapidshare.com/files/230296037/Utilities_Used.rar.html Ok, the Rapidshare files i posted are gone, so you will have to download as described in the solution. If you need more help, go here: http://www.dotsis.com/mobile_phone/sitemap/t-160491.html Some months later, someone else gave almost the same kind of solution here. http://www.dotsis.com/mobile_phone/sitemap/t-180123.html Note: the solutions were mean't to help view maps on Symbian phones, but i think now they ca even do for Windows Phones, iphones and others so read, extract what you want and use it. Hope it helps. Sam Kea

  Read the article

• Listing common SQL Code Smells.

  - by Phil Factor

  Once you’ve done a number of SQL Code-reviews, you’ll know those signs in the code that all might not be well. These ’Code Smells’ are coding styles that don’t directly cause a bug, but are indicators that all is not well with the code. . Kent Beck and Massimo Arnoldi seem to have coined the phrase in the "OnceAndOnlyOnce" page of www.C2.com, where Kent also said that code "wants to be simple". Bad Smells in Code was an essay by Kent Beck and Martin Fowler, published as Chapter 3 of the book ‘Refactoring: Improving the Design of Existing Code’ (ISBN 978-0201485677) Although there are generic code-smells, SQL has its own particular coding habits that will alert the programmer to the need to re-factor what has been written. See Exploring Smelly Code   and Code Deodorants for Code Smells by Nick Harrison for a grounding in Code Smells in C# I’ve always been tempted by the idea of automating a preliminary code-review for SQL. It would be so useful to trawl through code and pick up the various problems, much like the classic ‘Lint’ did for C, and how the Code Metrics plug-in for .NET Reflector by Jonathan 'Peli' de Halleux is used for finding Code Smells in .NET code. The problem is that few of the standard procedural code smells are relevant to SQL, and we need an agreed list of code smells. Merrilll Aldrich made a grand start last year in his blog Top 10 T-SQL Code Smells.However, I'd like to make a start by discovering if there is a general opinion amongst Database developers what the most important SQL Smells are. One can be a bit defensive about code smells. I will cheerfully write very long stored procedures, even though they are frowned on. I’ll use dynamic SQL occasionally. You can only use them as an aid for your own judgment and it is fine to ‘sign them off’ as being appropriate in particular circumstances. Also, whole classes of ‘code smells’ may be irrelevant for a particular database. The use of proprietary SQL, for example, is only a ‘code smell’ if there is a chance that the database will have to be ported to another RDBMS. The use of dynamic SQL is a risk only with certain security models. As the saying goes,  a CodeSmell is a hint of possible bad practice to a pragmatist, but a sure sign of bad practice to a purist. Plamen Ratchev’s wonderful article Ten Common SQL Programming Mistakes lists some of these ‘code smells’ along with out-and-out mistakes, but there are more. The use of nested transactions, for example, isn’t entirely incorrect, even though the database engine ignores all but the outermost: but it does flag up the possibility that the programmer thinks that nested transactions are supported. If anything requires some sort of general agreement, the definition of code smells is one. I’m therefore going to make this Blog ‘dynamic, in that, if anyone twitters a suggestion with a #SQLCodeSmells tag (or sends me a twitter) I’ll update the list here. If you add a comment to the blog with a suggestion of what should be added or removed, I’ll do my best to oblige. In other words, I’ll try to keep this blog up to date. The name against each 'smell' is the name of the person who Twittered me, commented about or who has written about the 'smell'. it does not imply that they were the first ever to think of the smell! Use of deprecated syntax such as *= (Dave Howard) Denormalisation that requires the shredding of the contents of columns. (Merrill Aldrich) Contrived interfaces Use of deprecated datatypes such as TEXT/NTEXT (Dave Howard) Datatype mis-matches in predicates that rely on implicit conversion.(Plamen Ratchev) Using Correlated subqueries instead of a join   (Dave_Levy/ Plamen Ratchev) The use of Hints in queries, especially NOLOCK (Dave Howard /Mike Reigler) Few or No comments. Use of functions in a WHERE clause. (Anil Das) Overuse of scalar UDFs (Dave Howard, Plamen Ratchev) Excessive ‘overloading’ of routines. The use of Exec xp_cmdShell (Merrill Aldrich) Excessive use of brackets. (Dave Levy) Lack of the use of a semicolon to terminate statements Use of non-SARGable functions on indexed columns in predicates (Plamen Ratchev) Duplicated code, or strikingly similar code. Misuse of SELECT * (Plamen Ratchev) Overuse of Cursors (Everyone. Special mention to Dave Levy & Adrian Hills) Overuse of CLR routines when not necessary (Sam Stange) Same column name in different tables with different datatypes. (Ian Stirk) Use of ‘broken’ functions such as ‘ISNUMERIC’ without additional checks. Excessive use of the WHILE loop (Merrill Aldrich) INSERT ... EXEC (Merrill Aldrich) The use of stored procedures where a view is sufficient (Merrill Aldrich) Not using two-part object names (Merrill Aldrich) Using INSERT INTO without specifying the columns and their order (Merrill Aldrich) Full outer joins even when they are not needed. (Plamen Ratchev) Huge stored procedures (hundreds/thousands of lines). Stored procedures that can produce different columns, or order of columns in their results, depending on the inputs. Code that is never used. Complex and nested conditionals WHILE (not done) loops without an error exit. Variable name same as the Datatype Vague identifiers. Storing complex data  or list in a character map, bitmap or XML field User procedures with sp_ prefix (Aaron Bertrand)Views that reference views that reference views that reference views (Aaron Bertrand) Inappropriate use of sql_variant (Neil Hambly) Errors with identity scope using SCOPE_IDENTITY @@IDENTITY or IDENT_CURRENT (Neil Hambly, Aaron Bertrand) Schemas that involve multiple dated copies of the same table instead of partitions (Matt Whitfield-Atlantis UK) Scalar UDFs that do data lookups (poor man's join) (Matt Whitfield-Atlantis UK) Code that allows SQL Injection (Mladen Prajdic) Tables without clustered indexes (Matt Whitfield-Atlantis UK) Use of "SELECT DISTINCT" to mask a join problem (Nick Harrison) Multiple stored procedures with nearly identical implementation. (Nick Harrison) Excessive column aliasing may point to a problem or it could be a mapping implementation. (Nick Harrison) Joining "too many" tables in a query. (Nick Harrison) Stored procedure returning more than one record set. (Nick Harrison) A NOT LIKE condition (Nick Harrison) excessive "OR" conditions. (Nick Harrison) User procedures with sp_ prefix (Aaron Bertrand) Views that reference views that reference views that reference views (Aaron Bertrand) sp_OACreate or anything related to it (Bill Fellows) Prefixing names with tbl_, vw_, fn_, and usp_ ('tibbling') (Jeremiah Peschka) Aliases that go a,b,c,d,e... (Dave Levy/Diane McNurlan) Overweight Queries (e.g. 4 inner joins, 8 left joins, 4 derived tables, 10 subqueries, 8 clustered GUIDs, 2 UDFs, 6 case statements = 1 query) (Robert L Davis) Order by 3,2 (Dave Levy) MultiStatement Table functions which are then filtered 'Sel * from Udf() where Udf.Col = Something' (Dave Ballantyne) running a SQL 2008 system in SQL 2000 compatibility mode(John Stafford)

  Read the article

• 10 tape technology features that make you go hmm.

  - by Karoly Vegh

  A week ago an Oracle/StorageTek Tape Specialist, Christian Vanden Balck, visited Vienna, and agreed to visit customers to do techtalks and update them about the technology boom going around tape. I had the privilege to attend some of his sessions and noted the information and features that took the customers by surprise and made them think. Allow me to share the top 10: I. StorageTek as a brand: StorageTek is one of he strongest names in the Tape field. The brand itself was valued so much by customers that even after Sun Microsystems acquiring StorageTek and the Oracle acquiring Sun the brand lives on with all the Oracle tapelibraries are officially branded StorageTek.See http://www.oracle.com/us/products/servers-storage/storage/tape-storage/overview/index.html II. Disk information density limitations: Disk technology struggles with information density. You haven't seen the disk sizes exploding lately, have you? That's partly because there are physical limits on a disk platter. The size is given, the number of platters is limited, they just can't grow, and are running out of physical area to write to. Now, in a T10000C tape cartridge we have over 1000m long tape. There you go, you have got your physical space and don't need to stuff all that data crammed together. You can write in a reliable pattern, and have space to grow too. III. Oracle has a market share of 62% worldwide in recording head manufacturing. That's right. If you are running LTO drives, with a good chance you rely on StorageTek production. That's two out of three LTO recording heads produced worldwide.  IV. You can store 1 Exabyte data in a single tape library. Yes, an Exabyte. That is 1000 Petabytes. Or, a million Terabytes. A thousand million GigaBytes. You can store that in a stacked StorageTek SL8500 tapelibrary. In one SL8500 you can put 10.000 T10000C cartridges, that store 10TB data (compressed). You can stack 10 of these SL8500s together. Boom. 1000.000 TB.(n.b.: stacking means interconnecting the libraries. Yes, cartridges are moved between the stacked libraries automatically.)  V. EMC: 'Tape doesn't suck after all. We moved on.': Do you remember the infamous 'Tape sucks, move on' Datadomain slogan? Of course they had to put it that way, having only had disk products. But here's a fun fact: on the EMCWorld 2012 there was a major presence of a Tape-tech company - EMC, in a sudden burst of sanity is embracing tape again. VI. The miraculous T10000C: Oracle StorageTek has developed an enterprise-grade tapedrive and cartridge, the T10000C. With awesome numbers: The Cartridge: Native 5TB capacity, 10TB with compression Over a kilometer long tape within the cartridge. And it's locked when unmounted, no rattling of your data.  Replaced the metalparticles datalayer with BaFe (bariumferrite) - metalparticles lose around 7% of magnetism within 30 days. BaFe does not. Yes we employ solid-state physicists doing R&D on demagnetisation in our labs. Can be partitioned, storage tiering within the cartridge!  The Drive: 2GB Cache Encryption implemented in HW - no performance hit 252 MB/s native sustained data rate, beats disk technology by far. Not to mention peak throughput.  Leading the tape while never touching the data side of it, protecting your data physically too Data integritiy checking (CRC recalculation) on tape within the drive without having to read it back to the server reordering data from tape-order, delivering it back in application-order  writing 32 tracks at once, reading them back for CRC check at once VII. You only use 20% of your data on a regular basis. The rest 80% is just lying around for years. On continuously spinning disks. Doubly consuming energy (power+cooling), blocking diskstorage capacity. There is a solution called SAM (Storage Archive Manager) that provides you a filesystem unifying disk and tape, moving data on-demand and for clients transparently between the different storage tiers. You can share these filesystems with NFS or CIFS for clients, and enjoy the low TCO of tape. Tapes don't spin. They sit quietly in their slots, storing 10TB data, using no energy, producing no heat, automounted when a client accesses their data.See: http://www.oracle.com/us/products/servers-storage/storage/storage-software/storage-archive-manager/overview/index.html VIII. HW supported for three decades: Did you know that the original PowderHorn library was released in '87 and has been only discontinued in 2010? That is over two decades of supported operation. Tape libraries are - just like the data carrying on tapecartridges - built for longevity. Oh, and the T10000C cartridge has 30-year archival life for long-term retention.  IX. Tape is easy to manage: Have you heard of Tape Storage Analytics? It is a central graphical tool to summarize, monitor, analyze dataflow, health and performance of drives and libraries, see: http://www.oracle.com/us/products/servers-storage/storage/tape-storage/tape-analytics/overview/index.html X. The next generation: The T10000B drives were able to reuse the T10000A cartridges and write on them even more data. On the same cartridges. We call this investment protection, and this is very important for Oracle for the future too. We usually support two generations of cartridges together. The current drive is a T10000C. (...I know I promised to enlist 10, but I got still two more I really want to mention. Allow me to work around the problem: ) X++. The TallBots, the robots moving around the cartridges in the StorageTek library from tapeslots to the drives are cableless. Cables, belts, chains running to moving parts in a library cause maintenance downtimes. So StorageTek eliminated them. The TallBots get power, commands, even firmwareupgrades through the rails they are running on. Also, the TallBots don't just hook'n'pull the tapes out of their slots, they actually grip'n'lift them out. No friction, no scratches, no zillion little plastic particles floating around in the library, in the drives, on your data. (X++)++: Tape beats SSDs and Disks. In terms of throughput (252 MB/s), in terms of TCO: disks cause around 290x more power and cooling, in terms of capacity: 10TB on a single media and soon more.  So... do you need to store large amounts of data? Are you legally bound to archive it for dozens of years? Would you benefit from automatic storage tiering? Have you got large mediachunks to be streamed at times? Have you got power and cooling issues in the growing datacenters? Do you find EMC's 180° turn of tape attitude interesting, but appreciate it at the same time? With all that, you aren't alone. The most data on this planet is stored on tape. Tape is coming. Big time.

  Read the article

• Xubuntu 13.10 64bit - Slow and buggy "log out" process?

  - by MrKatSwordfish

  I'm a Windows convert who has done only a little bit of dabbling in Ubuntu in the past (back in Dapper Drake a few years back). A lot has changes since then, and I've been yearning to jump back into linux again! So, having just bought a new SSD, I felt that this would be as good of a time as any to set up a dual-boot system again. I've messed around with Ubuntu 13.10 a bit, and while Unity has its issues, I think that it still needs some time to develop. I looked into XFCE and liked it a lot, so I went with Xubuntu. I've installed Xubuntu, and for the most part it's running smoothly and it a pleasure to work with. The customization is great and the minimalistic look and feel is really nice! But here's my problem, whenever I select the "Log Out" option from either the application menu, or the user profiles menu, my PC comes to a crawl, and the dialog box with all the options (shut down, restart, log out, etc.) takes maybe a minute or more to appear. I click the log out button, my PC is brought to a snail's pace, and I have to wait for what seems like an eternity for the logout options to appear! If i try to open something else (even a terminal window) while it's loading the logout options, that other program won't finish loading until the logout screen finally appears. Keep in mind, this is a pretty much vanilla install of Xubuntu 13.10 64bit, on a PC with an intel i7, an SSD, 6gb DDR3 RAM, and a new AMD 7770 gpu (drivers haven't been installed yet, though). Everything else runs fast, most applications open near-instantly! It must be an issue with how the logout options screen initializes or something, but I'm not sure exactly how I can fix it.. Edit - Extra Info: This problem is very consistent when using the "Log Out" buttons in Xubuntu. However, I've found that I'm able to reboot and shutdown much more quickly by going through the "Switch User" screen, and using the reboot or shutdown buttons on that screen. I'm nearly certain that it has something to do with the little Log Out options screen that appears when I select Log Out from the menu, and not the actual process of shutting down.. So what should I do? I really like XFCE so far, and I've never tried a non-ubuntu based distro before, but should I just switch to something else? Is there any known fix for this issue? Are there any work-arounds for logging out/shutting down/rebooting via the terminal so that I can avoid this irritating bug? Is there any that I can monitor the progress of the log out via terminal, allowing me to see which parts are causing the slow-down? What is the best way to report this bug to someone?

  Read the article

• Ask How-To Geek: Learning the Office Ribbon, Booting to USB with an Old BIOS, and Snapping Windows

  - by Jason Fitzpatrick

  You’ve got questions and we’ve got answers. Today we highlight how to master the new Office interface, USB boot a computer with outdated BIOS, and snap windows to preset locations. Learning the New Office Ribbon Dear How-To Geek, I feel silly asking this (in light of how long the new Office interface has been out) but my company finally got around to upgrading from Windows XP and Office 2000 so the new interface it totally new to me. Can you recommend any resources for quickly learning the Office ribbon and the new changes? I feel completely lost after two decades of the old Office interface. Help! Sincerely, Where the Hell is Everything? Dear Where the Hell, We think most people were with you at some point in the last few years. “Where the hell is…” could possibly be the slogan for the new ribbon interface. You could browse through some of the dry tutorials online or even get a weighty book on the topic but the best way to learn something new is to get hands on. Ribbon Hero turns learning the new Office features and ribbon layout into a game. It’s no vigorous round of Team Fortress mind you, but it’s significantly more fun than reading a training document. Check out how to install and configure Ribbon Hero here. You’ll be teaching your coworkers new tricks in no time. Boot via USB with an Old BIOS Dear How-To Geek, I’m trying to repurpose some old computers by updating them with lightweight Linux distros but the BIOS on most of the machines is ancient and creaky. How ancient? It doesn’t even support booting from a USB device! I have a large flash drive that I’ve turned into a master installation tool for jobs like this but I can’t use it. The computers in question have USB ports; they just aren’t recognized during the boot process. What can I do? USB Bootin’ in Boise Dear USB Bootin’, It’s great you’re working to breathe life into old hardware! You’ve run into one of the limitations of older BIOSes, USB was around but nobody was thinking about booting off of it. Fortunately if you have a computer old enough to have that kind of BIOS it’s likely to also has a floppy drive or a CDROM drive. While you could make a bootable CDROM for your application we understand that you want to keep using the master USB installer you’ve made. In light of that we recommend PLoP Boot Manager. Think of it like a boot manager for your boot manager. Using it you can create a bootable floppy or CDROM that will enable USB booting of your master USB drive. Make a CD and a floppy version and you’ll have everything in your toolkit you need for future computer refurbishing projects. Read up on creating bootable media with PLoP Boot Manager here. Snapping Windows to Preset Coordinates Dear How-To Geek, Once upon a time I had a company laptop that came with a little utility that snapped windows to preset areas of the screen. This was long before the snap-to-side features in Windows 7. You could essentially configure your screen into a grid pattern of your choosing and then windows would neatly snap into those grids. I have no idea what it was called or if was anymore than a gimmick from the computer manufacturer, but I’d really like to have it on my new computer! Bend and Snap in San Francisco, Dear Bend and Snap, If we had to guess, we’d guess your company must have had a set of laptops from Acer as the program you’re describing sounds exactly like Acer GridVista. Fortunately for you the application was extremely popular and Acer released it independently of their hardware. If, by chance, you’ve since upgraded to a multiple monitor setup the app even supports multiple monitors—many of the configurations are handy for arranging IM windows and other auxiliary communication tools. Check out our guide to installing and configuring Acer GridVista here for more information. Have a question you want to put before the How-To Geek staff? Shoot us an email at [email protected] and then keep an eye out for a solution in the Ask How-To Geek column. Latest Features How-To Geek ETC How to Upgrade Windows 7 Easily (And Understand Whether You Should) The How-To Geek Guide to Audio Editing: Basic Noise Removal Install a Wii Game Loader for Easy Backups and Fast Load Times The Best of CES (Consumer Electronics Show) in 2011 The Worst of CES (Consumer Electronics Show) in 2011 HTG Projects: How to Create Your Own Custom Papercraft Toy Download the New Year in Japan Windows 7 Theme from Microsoft Once More Unto the Breach – Facebook Apps Can Now Access Your Address and Phone Number Dial Zero Speeds You Through Annoying Customer Service Menus Complete Dropquest 2011 and Receive Free Dropbox Storage Desktop Computer versus Laptop Wallpaper The Kids Have No Idea What Old Tech Is [Video]

  Read the article

• Make Your 64 bit Computer Look like a Commodore 64

  - by Matthew Guay

  The Commodore 64 was one of the bestselling home computers ever, and many geeks got their first computing experience on one of these early personal computers. Here’s an easy way to revisit the early years of personal computing with a theme for Windows 7. With only 64Kb of ram and an 8 bit processor, the Commodore 64 is light-years behind today’s computers.  But with a Windows 7 themepack, you can turn back the years and give your computer a quick overhaul to look more like its ancient predecessor. Age Windows 7 with a click Download the Commodore 64 theme from PC World (link below), and unzip the files. Now, double-click on the Themepack file to apply the theme. This will open your Personalization panel and will automatically change your system fonts, window style, background, and more. Your desktop will go from your Windows 7 look… to a modified Windows 7 look that is reminiscent of the Commodore 64. Open an application to see all the changes … notice the old-style font in the Window boarder and menus. This theme also changes your Computer, Recycle Bin, and User folder icons to Commodore 64-inspired icons. And, if you want to go back to the standard Windows 7 look and feel, it’s only a click away in the Personalization dialog.  Right-click on your desktop, select Personalize, and then choose the theme you want.   Conclusion Although this doesn’t give you the real look and feel of the Commodore 64, it is still a fun way to experience a bit of computer nostalgia.  There are tons of excellent themes available for Windows 7, so check back for more exciting ways to customize your desktop! Link Download the Commodore 64 theme for Windows 7 Similar Articles Productive Geek Tips Make MSE Create a Restore Point Before Cleaning MalwareMake Ubuntu Automatically Save Changes to Your SessionMake Windows Vista Shut Down Services QuickerChange Your Computer Name in Windows 7 or VistaMake Windows 7 or Vista Log On Automatically TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Dark Side of the Moon (8-bit) Norwegian Life If Web Browsers Were Modes of Transportation Google Translate (for animals) Out of 100 Tweeters Roadkill’s Scan Port scans for open ports

  Read the article

• SQL Developer at Oracle Open World 2012

  - by thatjeffsmith

  We have a lot going on in San Francisco this fall. One of the most personal exciting bits, for what will be my 4th or 5th Open World, is that this will be my FIRST as a member of Team Oracle. I’ve presented once before, but most years it was just me pressing flesh at the vendor booths. After 3-4 days of standing and talking, you’re ready to just go home and not do anything for a few weeks. This time I’ll have a chance to walk around and talk with our users and get a good idea of what’s working and what’s not. Of course it will be a great opportunity for you to find us and get to know your SQL Developer team! 3.4 miles across and back – thanks Ashley for signing me up for the run! This year is going to be a bit crazy. Work wise I’ll be presenting twice, working a booth, and proctoring several of our Hands-On Labs. The fun parts will be equally crazy though – running across the Bay Bridge (I don’t run), swimming the Bay (I don’t swim), having my wife fly out on Wednesday for the concert, and then our first WhiskyFest on Friday (I do drink whisky though.) But back to work – let’s talk about EVERYTHING you can expect from the SQL Developer team. Booth Hours We’ll have 2 ‘demo pods’ in the Exhibition Hall over at Moscone South. Look for the farm of Oracle booths, we’ll be there under the signs that say ‘SQL Developer.’ There will be several people on hand, mostly developers (yes, they still count as people), who can answer your questions or demo the latest features. Come by and say ‘Hi!’, and let us know what you like and what you think we can do better. Seriously. Monday 10AM – 6PM Tuesday 9:45AM – 6PM Wednesday 9:45AM – 4PM Presentations Stop by for an hour, pull up a chair, sit back and soak in all the SQL Developer goodness. You’ll only have to suffer my bad jokes for two of the presentations, so please at least try to come to the other ones. We’ll be talking about data modeling, migrations, source control, and new features in versions 3.1 and 3.2 of SQL Developer and SQL Developer Data Modeler. Day Time Event Monday 10:454:45 What’s New in SQL Developer Why Move to Oracle Application Express Listener Tueday 10:1511:455:00 Using Subversion in Oracle SQL Developer Data Modeler Oracle SQL Developer Tips & Tricks Database Design with Oracle SQL Developer Data Modeler Wednesday 11:453:30 Migrating Third-Party Databases and Applications to Oracle Exadata 11g Enterprise Options and Management Packs for Developers Hands On Labs (HOLs) The Hands On Labs allow you to come into a classroom environment, sit down at a computer, and run through some exercises. We’ll provide the hardware, software, and training materials. It’s self-paced, but we’ll have several helpers walking around to answer questions and chat up any SQL Developer or database topic that comes to mind. If your employer is sending you to Open World for all that great training, the HOLs are a great opportunity to capitalize on that. They are only 60 minutes each, so you don’t have to worry about burning out. And there’s no homework! Of course, if you do want to take the labs home with you, many are already available via the Developer Day Hands-On Database Applications Developer Lab. You will need your own computer for those, but we’ll take care of the rest. Wednesday PL/SQL Development and Unit Testing with Oracle SQL Developer 10:15 Performance Tuning with Oracle SQL Developer 11:45 Thursday The Soup to Nuts of Data Modeling with Oracle SQL Developer Data Modeler 11:15 Some Parting Advice Always wanted to meet your favorite Oracle authors, speakers, and thought-leaders? Don’t be shy, walk right up to them and introduce yourself. Normal social rules still apply, but at the conference everyone is open and up for meeting and talking with attendees. Just understand if there’s a line that you might only get a minute or two. It’s a LONG conference though, so you’ll have plenty of time to catch up with everyone. If you’re going to be around on Tuesday evening, head on over to the OTN Lounge from 4:30 to 6:30 and hang out for our Tweet Meet. That’s right, all the Oracle nerds on Twitter will be there in one place. Be sure to put your Twitter handle on your name tag so we know who you are!

  Read the article

• Oracle Open World 2012: SQL Developer Recap

  - by thatjeffsmith

  Last week was the ‘big show’ in San Francisco. I was very happy to meet many of you in person. And many of you had questions – lots of questions! We had full or overflowing rooms for our sessions and hands-on-labs. The SQL Developer ‘booths’ were also slammed several times. So exciting to see so many of YOU excited about SQL Developer. It’s very cool to hear the stories of our tools saving you and your organizations so much time (and money!) Instead of doing a Day 0 – Day 9 recap, I thought I’d share with you the questions that I heard more than once. And just for giggles, I’ll throw in some answers as well So in no particular order… What’s the difference between Oracle SQL Developer & Oracle SQL Developer Data Modeler? Mathematically speaking – two words. But as far as the actual modeling features go, there’s no difference between the two applications. The same ‘code’ or features as it pertains to data modeling and design are in both tools. However, in SQL Developer you have all of the OTHER features fighting for real estate in the UI. So I have a general rule of thumb – if you spend MOST of your time in the database, use SQL Developer. And if you spend most of your time in the data model, run the separate and dedicated program, Oracle SQL Developer Data Modeler. Here’s a couple of screenshots to drive home the UI point: Oracle SQL Developer Oracle SQL Developer Data Modeler running INSIDE of SQL Developer. Notice how the Modeler menu items fold under the file menu? Oracle SQL Developer Data Modeler Easier to navigate and manipulate your models with the stand alone modeler. Just no worksheet to run your ad-hoc queries, etc. Don’t forget you can disable the Data Modeler inside of SQL Developer via the Extensions preference page. How can I model my table partitions? Partitioning is defined via the Physical model. So after you have finished your relational model, you need to generate a physical model. Oracle SQL Developer Data Modeler Physical Model and Partitioning Open the properties for your physical model table. Enable the ‘partitioned’ property. Once you do so, the ‘Partitioning’ page will activate. Lots and lots of partitioning support and options here But what about Interval Partitioning? An extension of range partitioning in 11gR2, we don’t currently support this partitioning scheme in SQL Developer. But we’re working on it! Can SQL Developer ignore column order when comparing models? Yes! After you start a model compare, one of your options is to disregard the order of an attribute or column definition. Tell SQL Developer you don’t care when your column shows up, just as long as it DOES show up. Wow, you got a lot of questions around modeling! Is that normal? Yes! While we appreciate that many folks inherit their applications and associated designs, new applications are being ‘born’ every day. Since both of our tools are free for anyone to design their new Oracle applications with, we attract a fair amount of attention I want to do a Hands On Lab. How do I get your software and instructional guides? Go here. Download VirtualBox. Then download the VB image. Import the appliance. Start it. Connect oracle/oracle on the OEL VM. Click on ‘Start Here’ in the desktop. Follow the instructions. If you need help, ask away! You went too fast in your Tips & Tricks session. Do you have cliff notes? Yes! And you’re SO close to finding them! Just go to my SQL Developer resources page. All of my tips are documented on this blog somewhere. I’ve indexed the most popular ones on the resource page. You can use the Search dialog on the right to find the rest. Or just send me a comment or question, and I’ll do my best to answer them as they come in.

  Read the article

• Multiple Monitors

  - by mroberts

  At my workplace .Net developers get pretty much the same equipment. A decent Dell workstation / Desktop, mine is a Dell Precision 390. One dual core 2.40 GHz. Eight GB RAM. Windows 7 Enterprise 64-bit. Two Dell 20.1 Monitors. I'm happy with this.  The machine is about 3 years old but still runs with some decent speed. New developers are getting a Dell workstation with dual quad processors. I just put in a request for myself and three other developers for an upgraded video card and two additional monitors, for a total of four monitors per person.  We suggested this card, BTW, mainly for the cost.  The move from one monitor to two was fantastic (one might even say life (or work) changing) and truly did increase productivity. Now what about going from 2 monitors to 4?  I'm sure the change is not as dramatic as one to two, but I can't help but to think four monitors is better than two.  But if four is better than two, should we have asked for six?!? Also what about mixing monitor types?  Right now my monitors are the older square type vs. wide-screen.  It's been rumored that we will be getting monitors out of current stock and they will be 22 inch wide-screens.  I understand this, recession and all.  2-20 inch square monitors with 2-22 inch wide-screen monitors...hmmmmm.  I'm thinking I'd rather get 2 additional 17 inch square monitors to put on each side of my 20's. Also, a question was raised about the layout of four monitors. By default, my thought was I'll just put them all on my desk, kinda in a line. I've heard others say they want to stack them in a 2 x 2 square. BTW, loving multi monitor support in Visual studio 2010! I’d love some comments on your experience with one, two, four, or however many monitors from a developers perspective.

  Read the article

• Integrating Oracle Forms Applications 11g Into SOA (4-6/Mai/10)

  - by Claudia Costa

  Workshop Description This is a Free workshop of 3 days is targeted at Oracle Forms professionals interested in integrating Oracle Forms into a Service Oriented Architecture. The workshop highlights how Forms can be part of a Service Oriented Architecture, how the Oracle Forms functionalities make it possible to integrate existing (or new) Forms applications with new or existing development utilizing the Service Oriented Architecture concepts. The goal is to understand the incremental approach that Forms provides to developers who need to extend their business platform to JEE, allowing Oracle Forms customers to retain their investment in Oracle Forms while leveraging the opportunities offered by complementing technologies. During the event the attendees will implement the Oracle Forms functionalities that make it possible to integrate with SOA. Register Now! Prerequisites ·         Knowledge of the Oracle Forms development environment (mandatory) ·         Basic knowledge of the Oracle database ·         Basic knowledge of the Java Programming Language ·         Basic knowledge of Oracle Jdeveloper or another Java IDE   System Requirements   This workshop requires attendees to provide their own laptops for this class. Attendee laptops must meet the following minimum hardware/software requirements:   ·         Laptop/PC with minimum 4 GB RAM ·         Oracle Database ·         Oracle Forms 11g R1 PS1 (WebLogic Server 10.1.3.2 + Portal, Forms, Reports and Discoverer ) ·         Oracle JDeveloper 11g R1 PS1 http://download.oracle.com/otn/java/jdeveloper/1112/jdevstudio11112install.exe ·         TCP-IP Loopback Adapter Installation (before the SOASuite installation) ·         Oracle SOASuite 11g R1 PS1 (without BAM component) When asked for an admin password, please use 'welcome1 http://download.oracle.com/otn/nt/middleware/11g/ofm_rcu_win_11.1.1.2.0_disk1_1of1.zip http://download.oracle.com/otn/nt/middleware/11g/ofm_soa_generic_11.1.1.2.0_disk1_1of1.zip ·         Oracle BI Publisher 10.1.3.4.1 http://download.oracle.com/otn/nt/ias/101341/bipublisher_windows_x86_101341.zip ·         Oracle BI Publisher Desktop 10.1.3.4. http://download.oracle.com/otn/nt/ias/101341/bipublisher_desktop_windows_x86_101341.zip   ·         At least 1 Oracle Forms solution already upgraded to the Oracle FMW 11g platform.   ------------------------------------------------------------------------------------------   Horário e Local:   4-6 de Maio / 9:30-18:00h Oracle, Porto Salvo Register Here Para mais informação por favor contacte: [email protected]

  Read the article

• SQL SERVER – Beginning of SQL Server Architecture – Terminology – Guest Post

  - by pinaldave

  SQL Server Architecture is a very deep subject. Covering it in a single post is an almost impossible task. However, this subject is very popular topic among beginners and advanced users.  I have requested my friend Anil Kumar who is expert in SQL Domain to help me write  a simple post about Beginning SQL Server Architecture. As stated earlier this subject is very deep subject and in this first article series he has covered basic terminologies. In future article he will explore the subject further down. Anil Kumar Yadav is Trainer, SQL Domain, Koenig Solutions. Koenig is a premier IT training firm that provides several IT certifications, such as Oracle 11g, Server+, RHCA, SQL Server Training, Prince2 Foundation etc. In this Article we will discuss about MS SQL Server architecture. The major components of SQL Server are: Relational Engine Storage Engine SQL OS Now we will discuss and understand each one of them. 1) Relational Engine: Also called as the query processor, Relational Engine includes the components of SQL Server that determine what your query exactly needs to do and the best way to do it. It manages the execution of queries as it requests data from the storage engine and processes the results returned. Different Tasks of Relational Engine: Query Processing Memory Management Thread and Task Management Buffer Management Distributed Query Processing 2) Storage Engine: Storage Engine is responsible for storage and retrieval of the data on to the storage system (Disk, SAN etc.). to understand more, let’s focus on the following diagram. When we talk about any database in SQL server, there are 2 types of files that are created at the disk level – Data file and Log file. Data file physically stores the data in data pages. Log files that are also known as write ahead logs, are used for storing transactions performed on the database. Let’s understand data file and log file in more details: Data File: Data File stores data in the form of Data Page (8KB) and these data pages are logically organized in extents. Extents: Extents are logical units in the database. They are a combination of 8 data pages i.e. 64 KB forms an extent. Extents can be of two types, Mixed and Uniform. Mixed extents hold different types of pages like index, System, Object data etc. On the other hand, Uniform extents are dedicated to only one type. Pages: As we should know what type of data pages can be stored in SQL Server, below mentioned are some of them: Data Page: It holds the data entered by the user but not the data which is of type text, ntext, nvarchar(max), varchar(max), varbinary(max), image and xml data. Index: It stores the index entries. Text/Image: It stores LOB ( Large Object data) like text, ntext, varchar(max), nvarchar(max),  varbinary(max), image and xml data. GAM & SGAM (Global Allocation Map & Shared Global Allocation Map): They are used for saving information related to the allocation of extents. PFS (Page Free Space): Information related to page allocation and unused space available on pages. IAM (Index Allocation Map): Information pertaining to extents that are used by a table or index per allocation unit. BCM (Bulk Changed Map): Keeps information about the extents changed in a Bulk Operation. DCM (Differential Change Map): This is the information of extents that have modified since the last BACKUP DATABASE statement as per allocation unit. Log File: It also known as write ahead log. It stores modification to the database (DML and DDL). Sufficient information is logged to be able to: Roll back transactions if requested Recover the database in case of failure Write Ahead Logging is used to create log entries Transaction logs are written in chronological order in a circular way Truncation policy for logs is based on the recovery model SQL OS: This lies between the host machine (Windows OS) and SQL Server. All the activities performed on database engine are taken care of by SQL OS. It is a highly configurable operating system with powerful API (application programming interface), enabling automatic locality and advanced parallelism. SQL OS provides various operating system services, such as memory management deals with buffer pool, log buffer and deadlock detection using the blocking and locking structure. Other services include exception handling, hosting for external components like Common Language Runtime, CLR etc. I guess this brief article gives you an idea about the various terminologies used related to SQL Server Architecture. In future articles we will explore them further. Guest Author  The author of the article is Anil Kumar Yadav is Trainer, SQL Domain, Koenig Solutions. Koenig is a premier IT training firm that provides several IT certifications, such as Oracle 11g, Server+, RHCA, SQL Server Training, Prince2 Foundation etc. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Security, SQL Server, SQL Tips and Tricks, SQL Training, T SQL, Technology

  Read the article

• Web.Config is Cached

  - by SGWellens

  There was a question from a student over on the Asp.Net forums about improving site performance. The concern was that every time an app setting was read from the Web.Config file, the disk would be accessed. With many app settings and many users, it was believed performance would suffer. Their intent was to create a class to hold all the settings, instantiate it and fill it from the Web.Config file on startup. Then, all the settings would be in RAM. I knew this was not correct and didn't want to just say so without any corroboration, so I did some searching. Surprisingly, this is a common misconception. I found other code postings that cached the app settings from Web.Config. Many people even thanked the posters for the code. In a later post, the student said their text book recommended caching the Web.Config file. OK, here's the deal. The Web.Config file is already cached. You do not need to re-cache it. From this article http://msdn.microsoft.com/en-us/library/aa478432.aspx It is important to realize that the entire <appSettings> section is read, parsed, and cached the first time we retrieve a setting value. From that point forward, all requests for setting values come from an in-memory cache, so access is quite fast and doesn't incur any subsequent overhead for accessing the file or parsing the XML. The reason the misconception is prevalent may be because it's hard to search for Web.Config and cache without getting a lot of hits on how to setup caching in the Web.Config file. So here's a string for search engines to index on: "Is the Web.Config file Cached?" A follow up question was, are the connection strings cached? Yes. http://msdn.microsoft.com/en-us/library/ms178683.aspx At run time, ASP.NET uses the Web.Config files to hierarchically compute a unique collection of configuration settings for each incoming URL request. These settings are calculated only once and then cached on the server. And, as everyone should know, if you modify the Web.Config file, the web application will restart. I hope this helps people to NOT write code! Steve WellensCodeProject

  Read the article

• Web.Config is Cached

  - by SGWellens

  There was a question from a student over on the Asp.Net forums about improving site performance. The concern was that every time an app setting was read from the Web.Config file, the disk would be accessed. With many app settings and many users, it was believed performance would suffer. Their intent was to create a class to hold all the settings, instantiate it and fill it from the Web.Config file on startup. Then, all the settings would be in RAM. I knew this was not correct and didn't want to just say so without any corroboration, so I did some searching. Surprisingly, this is a common misconception. I found other code postings that cached the app settings from Web.Config. Many people even thanked the posters for the code. In a later post, the student said their text book recommended caching the Web.Config file. OK, here's the deal. The Web.Config file is already cached. You do not need to re-cache it. From this article http://msdn.microsoft.com/en-us/library/aa478432.aspx It is important to realize that the entire <appSettings> section is read, parsed, and cached the first time we retrieve a setting value. From that point forward, all requests for setting values come from an in-memory cache, so access is quite fast and doesn't incur any subsequent overhead for accessing the file or parsing the XML. The reason the misconception is prevalent may be because it's hard to search for Web.Config and cache without getting a lot of hits on how to setup caching in the Web.Config file. So here's a string for search engines to index on: "Is the Web.Config file Cached?" A follow up question was, are the connection strings cached? Yes. http://msdn.microsoft.com/en-us/library/ms178683.aspx At run time, ASP.NET uses the Web.Config files to hierarchically compute a unique collection of configuration settings for each incoming URL request. These settings are calculated only once and then cached on the server. And, as everyone should know, if you modify the Web.Config file, the web application will restart. I hope this helps people to NOT write code!   Steve WellensCodeProject

  Read the article

• HPC Server Dynamic Job Scheduling: when jobs spawn jobs

  - by JoshReuben

  HPC Job Types HPC has 3 types of jobs http://technet.microsoft.com/en-us/library/cc972750(v=ws.10).aspx · Task Flow – vanilla sequence · Parametric Sweep – concurrently run multiple instances of the same program, each with a different work unit input · MPI – message passing between master & slave tasks But when you try go outside the box – job tasks that spawn jobs, blocking the parent task – you run the risk of resource starvation, deadlocks, and recursive, non-converging or exponential blow-up. The solution to this is to write some performance monitoring and job scheduling code. You can do this in 2 ways: manually control scheduling - allocate/ de-allocate resources, change job priorities, pause & resume tasks , restrict long running tasks to specific compute clusters Semi-automatically - set threshold params for scheduling. How – Control Job Scheduling In order to manage the tasks and resources that are associated with a job, you will need to access the ISchedulerJob interface - http://msdn.microsoft.com/en-us/library/microsoft.hpc.scheduler.ischedulerjob_members(v=vs.85).aspx This really allows you to control how a job is run – you can access & tweak the following features: max / min resource values whether job resources can grow / shrink, and whether jobs can be pre-empted, whether the job is exclusive per node the creator process id & the job pool timestamp of job creation & completion job priority, hold time & run time limit Re-queue count Job progress Max/ min Number of cores, nodes, sockets, RAM Dynamic task list – can add / cancel jobs on the fly Job counters When – poll perf counters Tweaking the job scheduler should be done on the basis of resource utilization according to PerfMon counters – HPC exposes 2 Perf objects: Compute Clusters, Compute Nodes http://technet.microsoft.com/en-us/library/cc720058(v=ws.10).aspx You can monitor running jobs according to dynamic thresholds – use your own discretion: Percentage processor time Number of running jobs Number of running tasks Total number of processors Number of processors in use Number of processors idle Number of serial tasks Number of parallel tasks Design Your algorithms correctly Finally , don’t assume you have unlimited compute resources in your cluster – design your algorithms with the following factors in mind: · Branching factor - http://en.wikipedia.org/wiki/Branching_factor - dynamically optimize the number of children per node · cutoffs to prevent explosions - http://en.wikipedia.org/wiki/Limit_of_a_sequence - not all functions converge after n attempts. You also need a threshold of good enough, diminishing returns · heuristic shortcuts - http://en.wikipedia.org/wiki/Heuristic - sometimes an exhaustive search is impractical and short cuts are suitable · Pruning http://en.wikipedia.org/wiki/Pruning_(algorithm) – remove / de-prioritize unnecessary tree branches · avoid local minima / maxima - http://en.wikipedia.org/wiki/Local_minima - sometimes an algorithm cant converge because it gets stuck in a local saddle – try simulated annealing, hill climbing or genetic algorithms to get out of these ruts   watch out for rounding errors – http://en.wikipedia.org/wiki/Round-off_error - multiple iterations can in parallel can quickly amplify & blow up your algo ! Use an epsilon, avoid floating point errors,  truncations, approximations Happy Coding !

  Read the article

< Previous Page | 234 235 236 237 238 239 240 241 242 243 244 245  | Next Page >