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  • SQL 2K5 - Multiple databases vs. Multiple files

    - by Bob Palmer
    Hey all, quick question. Our current legacy system was built using multiple distinct databases (about ten of them). These are all part of the same discreet system, and a large number of SPs and functionalty span multiple databases. There are also key relationships that span (for example, a header table may be in database A with history, etc. in database B). When deploying multiple copies of our app to the same server therefore, we have to use multiple instances (because the database names are coded into so many sprocs). We're evaluating the idea of taking these ten databases (about 30gb total with individual sizes ranging from 100mb to 10gb) and merging them into a single database. Currently, we have our databases spread accross multiple spindles for better IO. The question I have is whether or not there is any performance loss or benefit of having 10 different databases vs. 10 different database files? i.e. rather than having three databases (A, B, and C) Disk D: A.mdf (1gb) Disk E: B.mdf (4gb) Disk F: C.mdf (10gb) Disk G: A_Log.ldf, B_Log.ldf, C_Log.ldf have one database (X) Disk D: X1.mdf (5gb) Disk E: X2.mdf (5gb) Disk F: X3.mdf (5gb) Disk G: X1_log.ldf,X2_log.ldf,X3_log.ldf Thanks! -Bob

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  • dd oflag=direct 5x fast

    - by César
    I have Centos 6.2 in server with this specs: 2xCPU 16 Core AMD Opteron 6282 SE 64GB RAM Raid controller H700 1GB cache NV - 2HD 74GB SAS 15Krpm RAID1 stripe 16k (OS Centos 6.2) sda - 4HD 146GB SAS 15Krpm RAID10 stripe 16k (ext4 bs 4096, no barriers) sdb -> /vol01 Raid controller H800 1GB cache nv - MD1200 12HD 300GB SAS 15Krpm RAID10 stripe 256k (For DB Postgres 8.3.18) (ext4 bs 4096, stride 64, stripe-width 384, no barriers) sdc -> /vol02 I'm benchmarking IO speed with dd, and view thah if in RAID10 12 disk exec: dd if=/dev/zero of=DD bs=8M count=10000 oflag=direct 10000+0 records in 10000+0 records out 83886080000 bytes (84 GB) copied, 126,03 s, 666 MB/s but if I remove "oflag=direct" option obtain about 80 MB/s. In read benchmark, results are similar: dd of=/dev/null if=DD bs=8M count=10000 iflag=direct 10000+0 records in 10000+0 records out 83886080000 bytes (84 GB) copied, 79,5918 s, 1,1 GB/s If remove iflag=direct obtain 150MB/s... I don't understand this huge differences, on other machines y don't have this behavior. Can I have some kernel parameter misconfigured? Thanks!

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  • Online resizing of kvm guest root filesystem?

    - by Bittrance
    I have a Linux guest that uses an LVM volume directly as root file system (that is, there is no partition table). libvirt config looks thus: <os> <type arch='x86_64' machine='rhel6.4.0'>hvm</type> <kernel>/boot/vmlinuz-X.Y.Z.el6.x86_64</kernel> <initrd>/boot/initramfs-X.Y.Z.el6.x86_64.img</initrd> <cmdline>console=ttyS0 root=/dev/vda</cmdline> <boot dev='hd'/> </os> <disk type='block' device='disk'> <driver name='qemu' type='raw' cache='none' io='native'/> <source dev='/dev/vg/guest'/> <target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> </disk> From inside the guest: $ mount /dev/vda on / type ext4 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) tmpfs on /dev/shm type tmpfs (rw) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) Is it possible to resize the guest's root partition without rebooting the guest? Just doing lvextend on the host and resize2fs from the guest does not seem to be enough.

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  • Value of Itanium over x86_64 for Oracle Deployment

    - by Antitribu
    We are looking at a new environment to run our Oracle Database running on SUSE (potentially migrating to RedHat). Our database is approximately 100GB and performs adequately on our current hardware (x86_64) with approximately 6GB of ram allocated to it. We are growing quickly however and will require more performance shortly. Given the cost of Oracle licenses we would like to maximize the value from each license by choosing the most appropriate CPU to run the software on. The questions are: Are there substantial benefits to looking at Itanium hardware, are there any drawbacks? Is there a point where Itanium starts to scale out better? What are the long term support options for Itanium? Given the dominance of x86 would it be safer long term to stick with x86? On average what would be the performance benefit of implementing an Oracle database on Itanium over x86_64? Is this an issue at all or will other factors (IO/RAM) cap out first? If anyone can point me towards some solid documentation on comparisons between the two platforms that provides good case analysis of when to choose which I'm more than happy to accept that as an answer.

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  • Apache2 slow serving static while healthy

    - by user45339
    My Apache status looks like; 201 requests/sec - 98.8 kB/second - 504 B/request 85 requests currently being processed, 345 idle workers _____CCW_C_____C__C__C_R____C_WC_________C__C____CW__C__CCC_____ __C____W______C___C___CW__C_C______C__W_C__C_____CCC____C______R CC_C_______C___C____C______________C______C__C________________C_ ___________________C______________________C_______C___C_____C___ CC____C__C___R_____C_C_CC__________C___C___________R____C_C_C___ ______C______W_W__W___C____________________C__WCC__R__R_C_______ R__RC________________________C___R____W__C____.................. .................................................... Server load is average 2 on a 4 core machine. IO utilization is 10-15% and doesn't have many jumps over 70%. Machine has almost 4 gb free and uses 0 swap. The site on the machine is a PHP site. All PHP code is optimized and fast mostly when it gets accessed, however sometimes requests get stuck. Stuck meaning; no response for at least 10 sec. We debugged the PHP code, but it is quite optimal and fast. We spend a lot of time on it until we decided to test the requesting of: <html><body>test</body></html> test.html page. This static resource also gets 'stuck' in the same manner the php pages get 'stuck'. How is the possible given the health of the system? I tested the network, but, when the PHP shows 'slowness' in the site monitoring, the html test files also take (far longer) than 10 sec to load using; time lynx -dump http://127.0.0.1/test.html We are kind of desperate to solve this problem, but we cannot seem to tackle it.

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  • JVM system time runs faster than HP UNIX OS system time

    - by winston
    Hello I have the following output from a simple debug jsp: Weblogic Startup Since: Friday, October 19, 2012, 08:36:12 AM Database Current Time: Wednesday, December 12, 2012, 11:43:44 AM Weblogic JVM Current Time: Wednesday, December 12, 2012, 11:45:38 AM Line 1 was a recorded variable during WebLogic webapp startup. Line 2 was output from database query select sysdate from dual; Line 3 was output from java code new Date() I have checked from shell date command that line 2 output conforms with OS time. The output of line 3 was mysterious. I don't know how it comes from Java VM. On another machine with same setting, the same jsp output like this: Weblogic Startup Since: Tuesday, December 11, 2012, 02:29:06 PM Database Current Time: Wednesday, December 12, 2012, 11:51:48 AM Weblogic JVM Current Time: Wednesday, December 12, 2012, 11:51:50 AM Another machine: Weblogic Startup Since: Monday, December 10, 2012, 05:00:34 PM Database Current Time: Wednesday, December 12, 2012, 11:52:03 AM Weblogic JVM Current Time: Wednesday, December 12, 2012, 11:52:07 AM Findings: the pattern shows that the longer Weblogic startup, the larger the discrepancy of OS time with JVM time. Anybody could help on HP JVM? On HP UNIX, NTP was done daily. Anyway here comes the server versions: HP-UX machinex B.11.31 U ia64 2426956366 unlimited-user license java version "1.6.0.04" Java(TM) SE Runtime Environment (build 1.6.0.04-jinteg_28_apr_2009_04_46-b00) Java HotSpot(TM) Server VM (build 11.3-b02-jre1.6.0.04-rc2, mixed mode) WebLogic Server Version: 10.3.2.0 Java properties java.runtime.name=Java(TM) SE Runtime Environment java.runtime.version=1.6.0.04-jinteg_28_apr_2009_04_46-b00 java.vendor=Hewlett-Packard Co. java.vendor.url=http\://www.hp.com/go/Java java.version=1.6.0.04 java.vm.name=Java HotSpot(TM) 64-Bit Server VM java.vm.info=mixed mode java.vm.specification.vendor=Sun Microsystems Inc. java.vm.vendor="Hewlett-Packard Company" sun.arch.data.model=64 sun.cpu.endian=big sun.cpu.isalist=ia64r0 sun.io.unicode.encoding=UnicodeBig sun.java.launcher=SUN_STANDARD sun.jnu.encoding=8859_1 sun.management.compiler=HotSpot 64-Bit Server Compiler sun.os.patch.level=unknown os.name=HP-UX os.version=B.11.31

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  • Why Virtual Box won't give me option to create 64 bits guests?

    - by Eduardo Born
    My host is x64 bits Windows 8.1. I downloaded the latest Virtual Box (4.3) and I'm trying to create a VM with a 64 bits Ubuntu OS (ubuntu-12.04.3-desktop-amd64). When I go to New VM wizard, it doesn't give me option to select "Ubuntu (x64)" as I have seen in other people's screenshots, only just "Ubuntu". As a result, the ISO can't boot. I tried in another PC and Virtual Box gives the x64 variants to most listed OS... Control Panel shows x64 OS, x64 processor. My host laptop is a Sony Vaio VPCZ22UGX/N, Intel® Core™ i7-2640M processor. CPUz shows Vx-t is available on my processor, of course. Here is what I tried so far: I enabled IO APIC as required in the docs. I have virtualization enabled in the BIOS. It works fine in VMware. Check that Hyper-V is not running or even installed on my Windows. Same for VMware. I also tried running the command: VBoxManage modifyvm [vmname] --longmode on for that VM, but no change.. I think the issue is really that I can't select x64 variant of the Ubuntu OS for that VM. Other people seem to indicate that's a requirement, but I don't get that option for some reason. I spent a lot of time and can't find what's wrong... Anyone knows what could be missing here? Thank you very much!! Eduardo

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  • Migrating from tomcat to tc server - receiving java.sql.SQLException on startup

    - by user470184
    I'm receiving below error when I start tcServer. I do not receive this error on standalone version of tomcat. Is there extra config I need to add for tcServer ? WARNING: Unexpected exception resolving reference java.sql.SQLException: Io exception: The Network Adapter could not establish the connection at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112) at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:146) at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:255) at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:387) at oracle.jdbc.driver.PhysicalConnection.(PhysicalConnection.java:441) at oracle.jdbc.driver.T4CConnection.(T4CConnection.java:165) at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:35) at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:801) at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:277) at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:182) at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:699) at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:631) at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:485) at org.apache.tomcat.jdbc.pool.ConnectionPool.(ConnectionPool.java:143) at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:116) at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:103) at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:539) at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:237) at org.apache.naming.factory.ResourceFactory.getObjectInstance(ResourceFactory.java:140) at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:304) at org.apache.naming.NamingContext.lookup(NamingContext.java:793) at org.apache.naming.NamingContext.lookup(NamingContext.java:140) at org.apache.naming.NamingContext.lookup(NamingContext.java:781) at org.apache.naming.NamingContext.lookup(NamingContext.java:153) at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1028) at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:637) at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:238) at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:142) at org.apache.catalina.core.StandardServer.start(StandardServer.java:747) at org.apache.catalina.startup.Catalina.start(Catalina.java:595) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)

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  • Representing server state with a metric

    - by Sal
    I'm using Microsoft's Performance Monitor to dump logs of RAM, CPU, network, and disk usage from multiple servers. I'd like to get a single metric that captures the state of a given variable to a good extent. For instance, disk usage is pretty stable, so if I take a single reading that says I have 50% remaining disk space, that reading will give me an accurate measure for the day. (The servers aren't doing heavy IO writing.) However, the tricky part here is monitoring CPU and network usage. The logs currently dump the % CPU usage every ten seconds. If I take a straight average of the numbers, it may not represent reality, as % CPU will be much lower during the night than day. (We host websites that sell appliance items.) I'd like to get an average over a span during peak hours (about 5 hours in the day) and present a daily peak hour metric. Of course, there are most likely some readings that will come in as overly spiked (if multiple users pinged the server at once) or no use (a momentary idle state). Is there a standard distribution/test industries use in these situation?

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  • Performance associated with storing millions of files on NTFS

    - by Tim Brigham
    Does anyone have a method / formula, etc that I could use - hopefully based on both current and projected numbers of files - to project the 'right' length of the split and the number of nested folders? Please note that although similar it isn't quite the same as Storing a million images in the filesystem. I'm looking for a way to help make the theories outlined more generic. Assumptions I have 'some' initial number of files. This number would be arbitrary but large. Say 500k to 10m+. I have considered the underlying physical hardware disk IO requirements that would be necessary to support such an endeavor. Put another way As time progresses this store will grow. I want to have the best balance of current performance and as my needs increase. Say I double or triple my storage. I need to be able to address both current needs and projected future growth. I need to both plan ahead and not sacrifice too much of current performance. What I've come up with I'm already thinking about using a hash split every so many characters to split things out across multiple directories and keeping the trees even, very similar as outlined in the comments in the question above. It also avoids duplicate files, which would be critical over time. I'm sure that the initial folder structure would be different based on what I've outlined, and depending on the initial scale. As far as I can figure there isn't a one size fits all solution here. It would be horrendously time intensive to work something out experimentally.

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  • How to set CA cert file for LDAP backend server in smbpasswd configuration

    - by hayalci
    I am having a problem with smbpasswd, an LDAP backend server and SSL/TLS certificates. The client machine that I run smbpasswd on is a Debian Etch machine, and the Ldap server is Sun DS running on Solaris. All the following occurs on the client. When I disable SSL, by setting "ldap ssl = no" in smb.conf, the smbpasswd program works without errors. When I set "ldap ssl = start tls", the following messages are printed by smbpasswd and there is a long timeout period before any password is asked by it Failed to issue the StartTLS instruction: Connect error Connection to LDAP server failed for the 1 try! ..... long delay ..... New SMB password: Retype new SMB password: Failed to issue the StartTLS instruction: Connect error Connection to LDAP server failed for the 1 try! smbpasswd: /tmp/buildd/openldap2-2.1.30/libraries/liblber/io.c:702: ber_get_next: Assertion `0' failed. Aborted I conducted some tests with "ldapsearch -ZZ". It was not working at first, but after I added the TLS_CACERT line to /etc/ldap/ldap.conf, /etc/libnss-ldap.conf and /etc/pam_ldap.conf, it started working. So relevant TLS sections in all those files are: ssl start_tls tls_checkpeer no tls_cacertfile /path/to/ca-root.pem TLS_CACERT /path/to/ca-root.pem But the smbpasswd program continued giving the error. I tried creating /etc/smbldap-tools/smbldap.conf file with following content (after consulting debian docs for smbldap-tools package) But as I see, smbpasswd comes with samba-common package and does not use the configuration for smbldap-tools utilities. verify="optional" cafile="/path/to/ca-root.pem" My question is: How can I set which SSL CA Certificate is used by smbpasswd program ?

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  • ssh connection operation timed out using rsync

    - by Mark Molina
    I use rsync to backup my remote server on my local device but when I combine it with a cron job my ssh times out. Just to be clear, the data is stored on a remote server and I want it stored on my local server. The backup request must be sent from my local server to the remote server. The command for backup up the data is working when I just type it in terminal like this: rsync -chavzP --stats USERNAME@IPADDRES: PATH_TO_BACKUP LOCAL_PATH_TO_BACKUP but when I combine it with a cron job like this: 10 11 * * * rsync -chavzP --stats USERNAME@IP_ADDRESS: PATH_TO_BACKUP LOCAL_PATH_TO_BACKUP the ssh connection times out. When the cronjob executes it send a mail to the root user with the output like this: From local.xx.xx.xx Tue Jul 2 11:20:17 2013 X-Original-To: username Delivered-To: [email protected] From: [email protected] (Cron Daemon) To: [email protected] Subject: Cron <username@server> rsync -chavzP --stats USERNAME@IPADDRES: PATH_TO_BACKUP LOCAL_PATH_TO_BACKUP X-Cron-Env: <SHELL=/bin/sh> X-Cron-Env: <PATH=/usr/bin:/bin> X-Cron-Env: <LOGNAME=username> X-Cron-Env: <USER=username> X-Cron-Env: <HOME=/Users/username> Date: Tue, 2 Jul 2013 11:20:17 +0200 (CEST) ssh: connect to host IP_ADDRESS port XX: Operation timed out rsync: connection unexpectedly closed (0 bytes received so far) [receiver] rsync error: unexplained error (code 255) at /SourceCache/rsync/rsync-42/rsync/io.c(452) [receiver=2.6.9] So the rsync command is working when just typed in terminal but not when used by a cronjob. Can anybody explain this?

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  • Mysql master-master not replicating

    - by frankil
    I'm setting up a master-master mysql replication on two servers (db1 and db2). I started with setting up db2 as a slave to db1 and that works fine. But when I set up db1 as a slave to db2 it isn't replicating. On the face of it everything looks fine but the data isn't replicating. There are no errors in either of the error logs. The slave status is updating the bin log position. I have used mysqlbinlog to examine both the binlog on the db2 and the relay log on db1 and all of the queries are going in there, but not being executed to db1. "show slave status" on both servers shows that both the slave io and sql threads are "Yes" and that the relay log position is updated by the sql thread. Also on both servers: >echo "show processlist" | mysql | grep "system user" 166819 system user NULL Connect 3655 Waiting for master to send event NULL 166820 system user NULL Connect 3507 Has read all relay log; waiting for the slave I/O thread to update it NULL Relevant config for db1: server-id = 1 log-slave-updates replicate-same-server-id = 0 auto_increment_increment = 4 auto_increment_offset = 1 master-host = db2 master-port = 3306 master-user = slaveuser master-password = *** skip-slave-start sync_binlog = 1 binlog-ignore-db=mysql Config for db2 server-id = 2 log-slave-updates replicate-same-server-id = 0 auto_increment_increment = 4 auto_increment_offset = 2 master-host = db1 master-port = 3306 master-user = slaveuser master-password = *** sync_binlog = 1 relay-log=mysql-relay-bin binlog-ignore-db=mysql What else can I look for to make sure db1 executes the queries from db2?

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  • Rsync Push files from linux to windoes. ssh issue - connection refused

    - by piyush c
    For some reason I want to run a script to move files from Linux machine to Windows. I have installed cwRsync on my windows machine and able to connect to linux machine. When i execute following command: rsync -e "ssh -l "piyush"" -Wgovz --timeout 120 --delay-updates --remove-sent-files /usr/local/src/piyush/sync/* "[email protected]:/cygdrive/d/temp" Where 10.0.0.60 is my widows machine and I am running above command on Linux - CentOS 5.5. After running command I get following error message: ssh: connect to host 10.0.0.60 port 22: Connection refused rsync: connection unexpectedly closed (0 bytes received so far) [sender] rsync error: error in rsync protocol data stream (code 12) at io.c(463) [sender=2.6.8] [root@localhost sync]# ssh [email protected] ssh: connect to host 10.0.0.60 port 22: Connection refused I have modified my firewall settings on widows to allow all ports. I think this issue is due to SSH Daemon not present on my windows machine. So I tried installing OpenSSH on my machine and running ssh-agent but didn't helped. I tried similar command to run on my widows machine to pull files from Linux and its working fine. For some reason I want command for Linux machine so that I can embed it in a shell script. Can you suggest me if I am missing anything.

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  • Optimizing Disk I/O & RAID on Windows SQL Server 2005

    - by David
    I've been monitoring our SQL server for a while, and have noticed that I/O hits 100% every so often using Task Manager and Perfmon. I have normally been able to correlate this spike with SUSPENDED processes in SQL Server Management when I execute "exec sp_who2". The RAID controller is controlled by LSI MegaRAID Storage Manager. We have the following setup: System Drive (Windows) on RAID 1 with two 280GB drives SQL is on a RAID 10 (2 mirroed drives of 280GB in two different spans) This is a database that is hammered during the day, but is pretty inactive at night. The DB size is currently about 13GB, and is used by approximately 200 (and growing) users a day. I have a couple of ideas I'm toying around with: Checking for Indexes & reindexing some tables Adding an additional RAID 1 (with 2 new, smaller, HDs) and moving the SQL's Log Data File (LDF) onto the new RAID. For #2, my question is this: Would we really be increasing disk performance (IO) by moving data off of the RAID 10 onto a RAID 1? RAID 10 obviously has better performance than RAID 1. Furthermore, SQL must write to the transaction logs before writing to the database. But on the flip side, we'll be reducing both the size of the disks as well as the amount of data written to the RAID 10, which is where all of the "meat" is - thereby increasing that RAID's performance for read requests. Is there any way to find out what our current limiting factor is? (The drives vs. the RAID Controller)? If the limiting factor is the drives, then maybe adding the additional RAID 1 makes sense. But if the limiting factor is the Controller itself, then I think we're approaching this thing wrong. Finally, are we just wasting our time? Should we instead be focusing our efforts towards #1 (reindexing tables, reducing network latency where possible, etc...)?

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  • Outlook error-'Can't open e-mail folders.You must connect to Exchange w/ current profile before you can sync folders w/ your Outlook data file'

    - by Emilio
    Note that the error message I put in the title of this question is abbreviated. The actual error message is below. I have an Exchange account and using Outlook 2010 as the client. I run in Cached Exchange Mode and have an .OST file locally. Recently I uninstalled and reinstalled office. I set up a new mail profile when prompted by Outlook 2010 upon first execution of the program. In my initial attempt, I pointed the data file at my existing OST file. In my second attempt, I had Outlook create a fresh empty file. In both cases I'm getting the error 'Cannot open your default e-mail folders. You must connect to Microsoft Exchange with the current profile before you can synchronize your folders with your Outlook data file (.ost).', also shown in this screenshot -- http://drop.io/4rc9v9o/asset/outlook-error-png. I don't know how to connect with the current profile - that's what I thought I did when I created a new .OST file? I've had this problem for several days so my OST file is now out of date. Once I get things running I obviously want my active mailbox to update the OST, not the other way around.

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  • ZFS with L2ARC (SSD) slower for random seeks than without L2ARC

    - by Florian Kruse
    I am currently testing ZFS (Opensolaris 2009.06) in an older fileserver to evaluate its use for our needs. Our current setup is as follows: Dual core (2,4 GHz) with 4 GB RAM 3x SATA controller with 11 HDDs (250 GB) and one SSD (OCZ Vertex 2 100 GB) We want to evaluate the use of a L2ARC, so the current ZPOOL is: $ zpool status pool: tank state: ONLINE scrub: none requested config: NAME STATE READ WRITE CKSUM afstank ONLINE 0 0 0 raidz1 ONLINE 0 0 0 c11t0d0 ONLINE 0 0 0 c11t1d0 ONLINE 0 0 0 c11t2d0 ONLINE 0 0 0 c11t3d0 ONLINE 0 0 0 raidz1 ONLINE 0 0 0 c13t0d0 ONLINE 0 0 0 c13t1d0 ONLINE 0 0 0 c13t2d0 ONLINE 0 0 0 c13t3d0 ONLINE 0 0 0 cache c14t3d0 ONLINE 0 0 0 where c14t3d0 is the SSD (of course). We run IO tests with bonnie++ 1.03d, size is set to 200 GB (-s 200g) so that the test sample will never be completely in ARC/L2ARC. The results without SSD are (average values over several runs which show no differences) write_chr write_blk rewrite read_chr read_blk random seeks 101.998 kB/s 214.258 kB/s 96.673 kB/s 77.702 kB/s 254.695 kB/s 900 /s With SSD it becomes interesting. My assumption was that the results should be in worst case at least the same. While write/read/rewrite rates are not different, the random seek rate differs significantly between individual bonnie++ runs (between 188 /s and 1333 /s so far), average is 548 +- 200 /s, so below the value w/o SSD. So, my questions are mainly: Why do the random seek rates differ so much? If the seeks are really random, they should not differ much (my assumption). So, even if the SSD is impairing the performance it should be the same in each bonnie++ run. Why is the random seek performance worse in most of the bonnie++ runs? I would assume that some part of the bonnie++ data is in the L2ARC and random seeks on this data performs better while random seeks on other data just performs similarly like before.

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  • Linux - real-world hardware RAID controller tuning (scsi and cciss)

    - by ewwhite
    Most of the Linux systems I manage feature hardware RAID controllers (mostly HP Smart Array). They're all running RHEL or CentOS. I'm looking for real-world tunables to help optimize performance for setups that incorporate hardware RAID controllers with SAS disks (Smart Array, Perc, LSI, etc.) and battery-backed or flash-backed cache. Assume RAID 1+0 and multiple spindles (4+ disks). I spend a considerable amount of time tuning Linux network settings for low-latency and financial trading applications. But many of those options are well-documented (changing send/receive buffers, modifying TCP window settings, etc.). What are engineers doing on the storage side? Historically, I've made changes to the I/O scheduling elevator, recently opting for the deadline and noop schedulers to improve performance within my applications. As RHEL versions have progressed, I've also noticed that the compiled-in defaults for SCSI and CCISS block devices have changed as well. This has had an impact on the recommended storage subsystem settings over time. However, it's been awhile since I've seen any clear recommendations. And I know that the OS defaults aren't optimal. For example, it seems that the default read-ahead buffer of 128kb is extremely small for a deployment on server-class hardware. The following articles explore the performance impact of changing read-ahead cache and nr_requests values on the block queues. http://zackreed.me/articles/54-hp-smart-array-p410-controller-tuning http://www.overclock.net/t/515068/tuning-a-hp-smart-array-p400-with-linux-why-tuning-really-matters http://yoshinorimatsunobu.blogspot.com/2009/04/linux-io-scheduler-queue-size-and.html For example, these are suggested changes for an HP Smart Array RAID controller: echo "noop" > /sys/block/cciss\!c0d0/queue/scheduler blockdev --setra 65536 /dev/cciss/c0d0 echo 512 > /sys/block/cciss\!c0d0/queue/nr_requests echo 2048 > /sys/block/cciss\!c0d0/queue/read_ahead_kb What else can be reliably tuned to improve storage performance? I'm specifically looking for sysctl and sysfs options in production scenarios.

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  • load average in top and procs in vmstat

    - by Mingfei.hua
    As far as I know, the load average in top is the numbers of precess(threads) in running or uninterrupted sleep status, So it should be equal to (procs-r +1 )+ procs-b in vmstat, but in practice, this two number always have big gap. Any wrongs in my understanding, appreciate so much if some guys give me some guide. top - 05:34:50 up 1 day, 20:56, 5 users, load average: 2.83, 2.67, 1.62 Tasks: 79 total, 1 running, 78 sleeping, 0 stopped, 0 zombie Cpu(s): 6.8%us, 1.8%sy, 0.0%ni, 91.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.4%st Mem: 1758000k total, 582636k used, 1175364k free, 103932k buffers Swap: 917500k total, 0k used, 917500k free, 180868k cached procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st 0 0 0 1182524 103784 180860 0 0 1 9 6 53 7 2 91 0 0 0 0 0 1182524 103784 180860 0 0 0 36 70 117 0 0 100 0 0 0 0 0 1182516 103784 180860 0 0 0 0 73 132 0 1 100 0 0 0 0 0 1182516 103784 180860 0 0 0 0 60 127 0 0 100 0 0 1 0 0 1182516 103784 180860 0 0 0 0 62 102 0 0 100 0 0 0 0 0 1182628 103784 180860 0 0 0 0 289 238 1 2 97 0 0 2 0 0 1152160 103784 180892 0 0 0 8 1481 2371 54 12 34 0 0 1 0 0 1182192 103784 180860 0 0 0 0 681 834 19 4 78 0 0 0 0 0 1182200 103784 180860 0 0 0 0 80 147 0 1 100 0 0 0 0 0 1182200 103784 180860 0 0 0 0 53 107 0 0 100 0 0 0 0 0 1182208 103788 180856 0 0 0 72 64 123 0 0 100 1 0

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  • Squid: The request or reply is too large

    - by Ueli
    I have done a reverse proxy with an Apache in the background (on the same server). All works great but I can't open one page. I get the error "The request or reply is too large." In my cache.log contains: 2010/12/09 15:28:29| WARNING: http.c:971: HTTP header too large 2010/12/09 15:29:03| ctx: enter level 0: 'http://server/admin/cms/nav' 2010/12/09 15:29:03| httpProcessReplyHeader: Too large reply header 2010/12/09 15:29:03| ctx: exit level 0 In my squid.conf i disabled the limitations of the request and reply header, without success: reply_body_max_size 0 allow all request_body_max_size 0 Does someone know why that don't work? Thank you very much. Squid Version: Squid Cache: Version 2.7.STABLE3 configure options: '--prefix=/usr' '--exec_prefix=/usr' '--bindir=/usr/sbin' '--sbindir=/usr/sbin' '--libexecdir=/usr/lib/squid' '--sysconfdir=/etc/squid' '--localstatedir=/var/spool/squid' '--datadir=/usr/share/squid' '--enable-async-io' '--with-pthreads' '--enable-storeio=ufs,aufs,coss,diskd,null' '--enable-linux-netfilter' '--enable-arp-acl' '--enable-epoll' '--enable-removal-policies=lru,heap' '--enable-snmp' '--enable-delay-pools' '--enable-htcp' '--enable-cache-digests' '--enable-underscores' '--enable-referer-log' '--enable-useragent-log' '--enable-auth=basic,digest,ntlm,negotiate' '--enable-negotiate-auth-helpers=squid_kerb_auth' '--enable-carp' '--enable-follow-x-forwarded-for' '--with-large-files' '--with-maxfd=65536' 'amd64-debian-linux' 'build_alias=amd64-debian-linux' 'host_alias=amd64-debian-linux' 'target_alias=amd64-debian-linux' 'CFLAGS=-Wall -g -O2' 'LDFLAGS=' 'CPPFLAGS='

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  • Can't get rsync over sftp to work

    - by Patrik
    I'm trying to set up a backup system from an Ubuntu server to a Synology NAS (DS413j) using rsync and sftp. I have created a user for this that we can call ubuntu-backup. I have a directory in ubuntu-backup home directory called www where the backup will be saved. I have enabled Network Backup in DSM The user ubuntu-backup has full access to it's home directory Here is my rsync config file on the Synology NAS: #motd file = /etc/rsyncd.motd #log file = /var/log/rsyncd.log pid file = /var/run/rsyncd.pid lock file = /var/run/rsync.lock use chroot = no [NetBackup] path = /var/services/NetBackup comment = Network Backup Share uid = root gid = root read only = no list = yes charset = utf-8 auth users = root secrets file = /etc/rsyncd.secrets [ubuntu-backup] path = /volume1/homes/ubuntu-backup/www comment = Ubuntu Backup uid = ubuntu-backup gid = users read only = false auth users = ubuntu-backup secrets file = /etc/rsyncd.secrets The permissions on /volume1/homes/ubuntu-backup/www is ubuntu-backup:users 777 Here is the command i'm running. rsync -aHvhiPb /var/www/ [email protected]:./ The result: sending incremental file list ERROR: module is read only rsync error: syntax or usage error (code 1) at main.c(1034) [Receiver=3.0.9] rsync: connection unexpectedly closed (9 bytes received so far) [sender] rsync error: error in rsync protocol data stream (code 12) at io.c(605) [sender=3.0.9] If I'm running this: rsync -aHvhiPb /var/www/ [email protected] It looks like its sending files. No errors. But I cant find anything on the NAS.

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  • Website has become slower on a VPS, was much fast on a shared host. What's wrong?

    - by Arpit Tambi
    My shared host suspended my website stating system overload, so I moved my website to a VPS which has 4GB RAM. But for some reason the website has become very slow. This is the vmstat output - procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ r b swpd free buff cache si so bi bo in cs us sy id wa st 1 0 0 3050500 0 0 0 0 0 1 0 0 0 0 100 0 0 Here's the Apache Benchmark output for a STATIC html page I ran on the server itself - Benchmarking www.ask-oracle.com (be patient)...apr_poll: The timeout specified has expired (70007) Total of 20 requests completed Update: Server Config: List item Centos 5.6 4 cores cpu 4 GB RAM LAMP stack with APC Wordpress Only one website It takes almost double time to load now, same website was much fast on shared hosting. I know I need to tweak some settings but have no clue where to start from? I have already tried to optimize apache, mysql etc. Update 2: CPU usage is low, see uptime output: 11:09:02 up 7 days, 21:26, 1 user, load average: 0.09, 0.11, 0.09 Update 3: When I load any webpage, browser shows "Waiting" for a long time and then page loads quickly. So I suspect server can accept only limited connections and holds extra connections in a waiting state. How to check this? Update 4: Following is the output on executing netperf TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to localhost.localdomain (127.0.0.1) port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 9615.40 [root@ip-118-139-177-244 j3ngn5ri6r01t3]# Here are the Apache MPM settings from httpd.conf, do they look okay? <IfModule worker.c> StartServers 5 MaxClients 100 MinSpareThreads 50 MaxSpareThreads 250 ThreadsPerChild 125 MaxRequestsPerChild 10000 ServerLimit 100 </IfModule>

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  • How to find process that's using 100% of CPU

    - by Gabriel
    As i'm looking at htop and top i see that my processor usage is 100% allways. But i can not see any process that is using that much CPU. Htop shows me only 1-2 processes that use around 5% cpu time. Is there a way to find the processes that use that much cpu time? Here is the output of ps -eo pcpu,pid,user,args | sort -r -k1 | less %CPU PID USER COMMAND 0.8 20413 root jsvc.exec -user tomcat -cp ./bootstrap.jar -Djava.endorsed.dirs=../common/endorsed -outfile ../logs/catalina.out -errfile ../logs/catalina.err -verbose org.apache.catalina.startup.Bootstrap -security 0.3 631 mysql /usr/sbin/mysqld --basedir=/ --datadir=/var/lib/mysql --user=mysql --pid-file=/var/lib/mysql/mysql.pid --skip-external-locking 0.2 3380 root /usr/local/apache/bin/httpd -k restart -DSSL 0.2 24698 root tailwatchd 0.2 22472 root /usr/local/jdk/bin/java -Djava.util.logging.config.file=/usr/local/jakarta/tomcat/conf/logging.properties -Dfile.encoding=UTF8 -XX:MaxPermSize=128m -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.endorsed.dirs=/usr/local/jakarta/tomcat/common/endorsed -classpath /usr/local/jakarta/tomcat/bin/bootstrap.jar -Dcatalina.base=/usr/local/jakarta/tomcat -Dcatalina.home=/usr/local/jakarta/tomcat -Djava.io.tmpdir=/usr/local/jakarta/tomcat/temp org.apache.catalina.startup.Bootstrap start 0.1 32095 root cpanellogd - processing bandwidth 0.0 9733 root sleep 1m

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  • Homebrew large data cluster access for 2 user levels?

    - by Yegor
    The title probably makes little sense, so here is an example. I have a file hosting site, that serves a large amount of semi-randomly accessed files. The setup is as follows: High horsepower front-end +DB server that also does encoding for files that need encoding Fresh file server, which stores newly uploaded content, thats probably (and usually) rapidly accessible, which has 500GB of raided SSD storage, that can push over 3GBit of traffic. 3 cheap node servers, containing 2 x 750GB SATA drives in raid1, where files older than 2 weeks are archived, from the SSD server (mentioned above). Files on each server are accessed via subdomains (via modsec) in a straight forward fashion (server1.domain.com, server2.domain.com, etc) Where I have the problem is this. I introduced a "premium" service where people pay a small fee every month, and get ad-free, quick accesses to stuff on the site. Once they are logged in, they access same files via premium.server1.domain.com via a different modsec script, with a different pass phrase. That all works fine and dandy.... except the cheap node servers are all IO bound, so accessing the files on them via a different, unsaturated network makes no difference, since it cannot read off the drive fast enough. What would be a good way to make files on the site be accessible via 2 different network routes, 1 of which will be saturated (the "free network") while all other files are on an un-saturated "premium" network?

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  • Need help trying to diagnose Symmetrix SAN performance issues

    - by arcain
    I am helping to benchmark hardware for a new SQL Server instance, and the volume presented to the OS for the data files is carved from a set of spindles on a Symmetrix SAN. The server has yet to have SQL Server installed, so the only activity on the box is our benchmarking. Now, our storage engineers say that this volume and it's resources are dedicated to our new server (I don't have access to see the actual SAN config) however the performance benchmarks are troubling. For example, the numbers look good until suddenly, and randomly, we see in our IO benchmarking tool wait times of 100 seconds, and disk queue lengths of 255 in perfmon. This SAN has an 8 GB cache, plus there are other applications besides ours that use the SAN. I'm wondering if (even though the spindles for our volumes should be dedicated to us) the cache may be getting hammered during the performance testing, or perhaps the spindles our volumes are on aren't really dedicated to us. We're not getting much traction from our storage engineers in helping us track down the problem, so if anybody has experience with diagnosing a problem like this and would like to share insights and troubleshooting methodologies, I'd appreciate it.

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