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  • Commvault Oracle RMAN Restore to new host

    - by Glenn Stauffer
    We use Commvault Simpana 8 and I have a situation where I have backups of an Oracle database on tape that were taken from Host A. Host A suffered a disk failure (lost its raid configuration) and the sys admins are trying to restore it; in the meantime, I'd working to bring the database back up on another host - Host B. I'm running into problems and am trying to sort out the parameters that need to be passed to the Commvault media agent to get this to work. Unfortunately, I do not have access to Commvault support and the backup person is unavailable. Any one have a clue? The backups are there and the media agent reported a successful write when they ran last night. This is what fails: RMAN run { allocate channel t1 device type sbt_tape parms='SBT_LIBRARY=/usr/local/galaxy/Base/libobk.so,BLKSIZE=262144, ENV=(CvClientName=dbsrv2,CvInstanceName=Instance001, CVOraRacDBName=BBDB, CVOraRACDBClientName=BBDB)'; restore spfile to pfile '/tmp/bbdb.ora' from autobackup; }2 3 4 allocated channel: t1 channel t1: sid=34 devtype=SBT_TAPE channel t1: CommVault Systems for Oracle: Version 7.0.0(Build76) Starting restore at 09-MAY-10 channel t1: looking for autobackup on day: 20100509 channel t1: autobackup found: c-3941155360-20100509-01 released channel: t1 RMAN-00571: =========================================================== RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS =============== RMAN-00571: =========================================================== RMAN-03002: failure of restore command at 05/09/2010 18:01:35 ORA-19870: error reading backup piece c-3941155360-20100509-01 ORA-19507: failed to retrieve sequential file, handle="c-3941155360-20100509-01", parms="" ORA-27029: skgfrtrv: sbtrestore returned error ORA-19511: Error received from media manager layer, error text: sbtrestore: Job[0] thread[26316]: InitializeCLRestore() failed.

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  • Commvault Oracle RMAN Restore to new host

    - by Glenn Stauffer
    We use Commvault Simpana 8 and I have a situation where I have backups of an Oracle database on tape that were taken from Host A. Host A suffered a disk failure (lost its raid configuration) and the sys admins are trying to restore it; in the meantime, I'd working to bring the database back up on another host - Host B. I'm running into problems and am trying to sort out the parameters that need to be passed to the Commvault media agent to get this to work. Unfortunately, I do not have access to Commvault support and the backup person is unavailable. Any one have a clue? The backups are there and the media agent reported a successful write when they ran last night. This is what fails: run { allocate channel t1 device type sbt_tape parms='SBT_LIBRARY=/usr/local/galaxy/Base/libobk.so,BLKSIZE=262144, ENV=(CvClientName=dbsrv2,CvInstanceName=Instance001, CVOraSID=BBPROD)'; restore spfile to pfile '/tmp/bbdb.ora' from autobackup; } allocated channel: t1 channel t1: sid=34 devtype=SBT_TAPE channel t1: CommVault Systems for Oracle: Version 7.0.0(Build76) Starting restore at 09-MAY-10 channel t1: looking for autobackup on day: 20100509 channel t1: autobackup found: c-3941155360-20100509-01 released channel: t1 RMAN-00571: =========================================================== RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS =============== RMAN-00571: =========================================================== RMAN-03002: failure of restore command at 05/09/2010 18:01:35 ORA-19870: error reading backup piece c-3941155360-20100509-01 ORA-19507: failed to retrieve sequential file, handle="c-3941155360-20100509-01", parms="" ORA-27029: skgfrtrv: sbtrestore returned error ORA-19511: Error received from media manager layer, error text: sbtrestore: Job[0] thread[26316]: InitializeCLRestore() failed.

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  • Can a CNAME be a hostname

    - by pulegium
    This is bit of a theological question, but nonetheless... So, a server has a hostname, let's say the fqdn is hostname.example.com (to be really precise about what I mean, this is the name that is set in /etc/sysconfig/network). The very same server has multiple interfaces on different subnets. Let's say the IPs are 10.0.0.1 and 10.0.1.1. Now the question is, is it theoretically (mind you, this is important, I know that practically it works, but I'm interested in purely academic answer) allowed to have the following setup: interface1.example.com. IN A 10.0.0.1 interface2.example.com. IN A 10.0.1.1 hostname.example.com. IN CNAME interface1.example.com. OR should it rather be: hostname.example.com. IN A 10.0.0.1 interface2.example.com. IN A 10.0.1.1 interface1.example.com. IN CNAME hostname.example.com. I guess it's obvious which one is making more sense from the management/administration POV, but is it technically correct? The argument against the first setup is that a reverse lookup to 10.0.0.1 returns interface1.example.com and not what one might expect (ie the hostname: hostname.example.com), so the forward request and then sub sequential reverse lookups would return different results. Now, as I said, I want a theoretical answer. Links to RFC sections etc, that explicitly allows or disallows use of CNAME name as a hostname. If there's none, that's fine too, I just need to confirm. I failed to find any explicit statements so far, bar this book, where this situation is given as an example and implies that it can be done as one of the ways to avoid MX records pointing to a CNAME.

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  • mdadm cron job sends email that cron has run

    - by Andrew
    I've got an Ubuntu 8.04 server using mdadm to create several RAID1 arrays. I created /etc/cron.hourly/mdadm as follows: #! /bin/sh set -e mdadm --monitor /dev/md0 /dev/md3 /dev/md4 --oneshot (Yes, the array numbers are not sequential, and I'm not using --scan beacuse I have a degraded array that may or may not have been used as swap and I can't delete, but I think that's a separate issue. If it's the underlying cause of this, I need to fix it.) mdadm sends me email (configured in the /etc/mdadm/mdadm.conf) on DegradedArray etc. events. This is the desired behaviour. What is not desired, and I can't work out, is why cron is sending me (relatively pointless) emails, via an alias in /etc/aliases: From: root@<hostname> (Cron Daemon) To: root@<hostname> Subject: Cron <root@<hostname>> cd / && run-parts --report /etc/cron.hourly Content-Type: text/plain; charset=ANSI_X3.4-1968 X-Cron-Env: <SHELL=/bin/sh> X-Cron-Env: <PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin> X-Cron-Env: <HOME=/root> X-Cron-Env: <LOGNAME=root> Message-Id: <id@hostname> Date: Fri, 7 May 2010 13:17:01 +0930 (CST) /etc/cron.hourly/mdadm: mdadm: Monitor using email address "<root_alias@domain>" from config file I've got a dozen other servers behaving correctly (mdadm sends email, cron doesnt') with identical /etc/crontab files: # /etc/crontab: system-wide crontab # <snip comments> SHELL=/bin/sh PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin # m h dom mon dow user command 17 * * * * root cd / && run-parts --report /etc/cron.hourly <snip anacron jobs> Should I simply remove the --report, or is there something else in my cron config somewhere causing this?

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  • HP Storageworks 448 tape drive input/output error with Ubuntu

    - by Dan D
    I'm trying to set a backup to tape of a machine using flexbackup. However any attempt to write to the tape drive (via either flexbackup or just tar) results in "/dev/st0: Input/output error" The machine seems to recognise the drive (HP Storageworks Ultrium 448) and that there's a tape in it and "mt status" seems to work... "mt -f /dev/st0 rewind" or "erase" throw no errors... root@stor001:/# mt status SCSI 2 tape drive: File number=0, block number=0, partition=0. Tape block size 0 bytes. Density code 0x42 (LTO-2). Soft error count since last status=0 General status bits on (41010000): BOT ONLINE IM_REP_EN root@stor001:/# cat /proc/scsi/scsi Attached devices: Host: scsi0 Channel: 00 Id: 00 Lun: 00 Vendor: HL-DT-ST Model: DVDRAM GSA-4084N Rev: KS02 Type: CD-ROM ANSI SCSI revision: 05 Host: scsi2 Channel: 00 Id: 03 Lun: 00 Vendor: HP Model: Ultrium 2-SCSI Rev: S65D Type: Sequential-Access ANSI SCSI revision: 03 "tell" does however root@stor001:/# mt -f /dev/st0 tell /dev/st0: Input/output error Based on a forum post I found, I tried: root@stor001:/# dd if=/dev/zero of=/dev/nst0 bs=1024 count=10 10+0 records in 10+0 records out 10240 bytes (10 kB) copied, 5.0815 s, 2.0 kB/s which gave the person on the forum an error but seems to work for me. If anyone has any suggestions, I'm all ears...

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  • Backing up VMs to a tape drive

    - by Aljoscha Vollmerhaus
    I've got myself one of these fancy tape drives, HP LTO2 with 200/400 GB cartridges. The st driver reports it like this: scsi 1:0:0:0: Sequential-Access HP Ultrium 2-SCSI T65D I can store and retrieve files like a charm using tar, both tar cf /dev/st0 somedirectory and tar xf /dev/st0 work flawless. However, what I really would like to backup are LVM LVs. They contain entire virtual machines with varying partition layouts, so using mount and tar is not an option. I've tried using something like dd if=/dev/VG/LV bs=64k of=/dev/st0 to achieve this, but there seem to be various problems associated with this approach. Firstly, I would like to be able to store more than 1 LV on a single tape. Now I guess I could seek to concatenate the data on the tape, but I think this would not work very well in an automated scenario with many different LVs of various sizes. Secondly, I would like to store a small XML file along with the raw data that contains some information about the VM contained in the LV. I could dump everything to a directory and tar it up - not very desirable, I would have to set aside huge amounts of scratch space. Is there an easier way to achieve this? Thirdly, from googling around it seems like it would be wise to use something like mbuffer when writing to the tape, to prevent what wikipedia calls "shoe-shining" the tape. However, I can't get anything useful done with mbuffer. The mbuffer man page suggests this for writing to a tape device: mbuffer -t -m 10M -p 80 -f -o $TAPE So I've tried this: dd if=/dev/VG/LV | mbuffer -t -m 10M -p 80 -f -d 64k -o /dev/st0 Note the added "-d 64k" to account for the 64k block size of the tape. However, reading data back from a tape written in this way never seems to yield any useful results - dd has been running for ages now, and managed to transfer only 361M of data from the tape. What's wrong here?

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  • How to direct reverse proxy requests using wildcard vhosts

    - by HonoredMule
    I'm interested in running a reverse proxy with 2-3 virtual machines behind it. Each internal server will run multiple virtual hosts, and rather than manually configuring each individual vhost on the proxy (a variety of vhosts come and go too often for this to be practical), I would like to use something which can employ pattern matching in a sequential order to find the appropriate back-end server. For example: Server 1: *.dev.mysite.com Server 2: *.stage.mysite.com Server 3: *.mysite.com, dev.mysite.com, stage.mysite.com, mysite.com Server 4: * In the above configuration, task.dev.mysite.com would go to Server 1, dev.mysite.com would go to Server 3, yoursite.stage.mysite.com to Server 2, www.mysite.com to Server 3, and yoursite.com to Server 4. I've looked into using Squid, Varnish, and nginx so far. I have my opinions regarding their respective desirability and general suitability, but it's not readily apparent if any of them can handle dynamic server selection in this manner and not require per-vhost configuration. Apache on the other hand can do this handily and simply, but otherwise (aside from being well-known and familiar) seems very poorly suited to the partly-performance-serving task. Performance isn't actually a major concern yet, but it seems foolish to use Apache if another system will perform far better and can also handle the desired 'hands-free' configuration. But so is frequently having to adjust the gateway for all production services and risk network-wide outage...and so also is setting oneself up for longer downtime later if Apache becomes a too-small bottleneck. Which of these (or other) reverse proxies can do it/would do it best? And maybe I should post this as a separate question, but if Apache is the only practical option, how safe/reliable/predictable is apache-mpm-event in apache2.2 (Ubuntu 12.04.1) particularly for a dedicated reverse proxy? As I understand it the Event MPM was declared "safe" as of 2.4 but it's unclear whether reaching stability in 2.4 has any implications for the older (2.2) versions available in official/stable package channels of various distros.

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  • Raid-5 Performance per spindle scaling

    - by Bill N.
    So I am stuck in a corner, I have a storage project that is limited to 24 spindles, and requires heavy random Write (the corresponding read side is purely sequential). Needs every bit of space on my Drives, ~13TB total in a n-1 raid-5, and has to go fast, over 2GB/s sort of fast. The obvious answer is to use a Stripe/Concat (Raid-0/1), or better yet a raid-10 in place of the raid-5, but that is disallowed for reasons beyond my control. So I am here asking for help in getting a sub optimal configuration to be as good as it can be. The array built on direct attached SAS-2 10K rpm drives, backed by a ARECA 18xx series controller with 4GB of cache. 64k array stripes and an 4K stripe aligned XFS File system, with 24 Allocation groups (to avoid some of the penalty for being raid 5). The heart of my question is this: In the same setup with 6 spindles/AG's I see a near disk limited performance on the write, ~100MB/s per spindle, at 12 spindles I see that drop to ~80MB/s and at 24 ~60MB/s. I would expect that with a distributed parity and matched AG's, the performance should scale with the # of spindles, or be worse at small spindle counts, but this array is doing the opposite. What am I missing ? Should Raid-5 performance scale with # of spindles ? Many thanks for your answers and any ideas, input, or guidance. --Bill Edit: Improving RAID performance The other relevant thread I was able to find, discusses some of the same issues in the answers, though it still leaves me with out an answer on the performance scaling.

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  • OpenSSL: how to setup an OCSP server for checking third-party certificates?

    - by StackedCrooked
    I am testing the Certificate Revocation functionality of a CMTS device. This requires me to setup a OCSP responder. Since it will only be used for testing I assume that the minimal implementation provided by OpenSSL should suffice. I have extracted the a certificate from a cable modem, copied it to my PC and converted it to the PEM format. Now I want to register it in the OpenSSL OCSP database and start a server. I have completed all these steps, but when I do a client request my server invariably responds with "unknown". It seems to be completely unaware of my certificate's existence. I would greatly appreciate if anyone would be willing to have a look at my code. For your convenience, I have created a single script consisting of a sequential list of all used commands, from setting up the CA until starting the server: http://code.google.com/p/stacked-crooked/source/browse/trunk/Misc/OpenSSL/AllCommands.sh You can also find the custom config file and the certificate that I am testing with: http://code.google.com/p/stacked-crooked/source/browse/trunk/Misc/OpenSSL/ Any help would be greatly appreciated.

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  • OpenSSL: how to setup an OCSP server for checking third-party certificates?

    - by StackedCrooked
    I am testing the Certificate Revocation functionality of a CMTS device. This requires me to setup a OCSP responder. Since it will only be used for testing I assume that the minimal implementation provided by OpenSSL should suffice. I have extracted the a certificate from a cable modem, copied it to my PC and converted it to the PEM format. Now I want to register it in the OpenSSL OCSP database and start a server. I have completed all these steps, but when I do a client request my server invariably responds with "unknown". It seems to be completely unaware of my certificate's existence. I would greatly appreciate if anyone would be willing to have a look at my code. For your convenience, I have created a single script consisting of a sequential list of all used commands, from setting up the CA until starting the server: http://code.google.com/p/stacked-crooked/source/browse/trunk/Misc/OpenSSL/AllCommands.sh You can also find the custom config file and the certificate that I am testing with: http://code.google.com/p/stacked-crooked/source/browse/trunk/Misc/OpenSSL/ Any help would be greatly appreciated.

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  • How to choose the most optimal RAID settings on PE2950

    - by javano
    I have some Dell PowerEdge 2950's with 4x 15k, 150GB Cheetah SAS drives in them. They are going to be VM hosts, CentOS running ESXi with Windows Server 2k8 guests. Some guests will be hosting IIS servers, and others MSSQL servers. I am trying to set the RAID virtual disks settings and can't decide which is more optimal given this situation; Read Policy: Out of Read-Ahead, No-Read-Ahead and Adaptive Read-Ahead, the default is Read-Ahead. I will be making large sequential writes initially, writing out blank images for virtual machine hard drives (lets say 30GBs from /dev/zero for example) so Read-Ahead seems good at first. But within the virtual machines reads could be random from anywhere within their file systems as they are IIS and MSSQL servers, so perhaps No-Read-Ahead is a better idea? Now I think Adaptive Read-Ahead would be better then as a compromise but I don't know much about this option, how does it compare in performance to the others? Write Policy: write-back caching, write-through caching, the default is write-back caching. The default of write-back caching is safer than write-through caching but at a performance expense. My thinking here is that in the event of power loss for example, it seems more likely in my head (this is why I need some clarification!) that damage will occur to a guest VM with write-back caching enabled, so I should favour write-through? I have searched around and there is obviously no definitive answer, so I would like to find out what is best for my situation.

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  • Network Load Balancing and AnyCast Routing

    - by user126917
    Hi All can anyone advise on problems with the following? I am planning on installing the following setup on my estate: I have 2 sites that both have a large amount of users. Goals are to keep things simple for the users and to have automatic failover above the database level. Our Database will exist at the primary site and be async mirrored to the secondary site with manual failover procedures.The database generate sequential ID's so distributing it is not an option. I plan to site IIS boxes at both sites with all of the business logic on them and heavy operations. The connections to SQL will be lightweight and DB reads will be cached on IIS. On this layer I plan to use Windows network load balancing and have the same IP or IPs across all IIS boxes at both sites. This way there will be automatic failover and no single point of failure. Also users can have one web address regardless of which site they are in automatically be network load balanced to their local IIS. This is great but obviously our two sites are on different subnets and as this will be one IP address with most of our traffic we can't go broadcasting everything across the link between the sites. To solve this problem we plan to use AnyCast routing over our network layer to route the traffic to the most local box that is listening which will be defined by the network load balancing. Has anyone used this setup before? Can anyone think of any issues with this? Also some specifics I can't find anywhere at the moment. If my Windows box is assigned an IP and listening on that IP but network load balancing is not accepting specific traffic then will AnyCast route away from that? Also can I AnyCast on a socket level?

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  • How to move or delete files from a folder containing 2 million files on an NTFS drive?

    - by Beau
    The issue is that any modification to the directory locks up Explorer indefinitely, though Samba access to other directories still works. I've tried moving files locally and over Samba. Even enumerating the directory to get the list of files locks up the computer indefinitely. I tried using Python's win32file.FindFilesIterator to iterate the files but that also hangs. My idea was to move each file to a different directory (in a directory above the directory we're dealing with) based on its timestamp, so that we'd have at most a thousand or so files in each directory... But since I can't even enumerate the files, that's been a non-starter. If I have to give up and just nuke the directory I'm willing to do that, but a standard delete also hangs indefinitely. I have set these two parameters to increase speed and they also did not help the issue: R:\>fsutil behavior query disablelastaccess disablelastaccess = 1 R:\>fsutil behavior query disable8dot3 disable8dot3 = 1 These are all sequential images that would have run into the 'bug' with 8.3 filenames whereby many similarly named files in one directory can take a long time to compute 8.3 filenames. From what I understand this data is stored in the file system even after disable8dot3 is enabled, so it may still be contributing to the problem. Any ideas?

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  • How to move your Windows User Profile to another drive in Windows 8

    - by Mark
    I like to have my user folder on a different drive (D:) than my OS is (C:). Reading the following post I decided to give it a try. All went quite well, untill I found out that my Windows 8 Apps won't execute anymore (other than that I didn't noticed any problems). My apps do work, while using an account that isn't moved. In the eventviewer I've found error messages like these: App <Microsoft.MicrosoftSkyDrive> crashed with an unhandled Javascript exception. App details are as follows: Display Name:<SkyDrive>, AppUserModelId: <microsoft.microsoftskydrive_8wekyb3d8bbwe!Microsoft.MicrosoftSkyDrive> Package Identity:<microsoft.microsoftskydrive_16.4.4204.712_x64__8wekyb3d8bbwe> PID:<4452>. The details of the JavaScript exception are as follows Exception Name:<WinRT error>, Description:<Loading the state store failed. > , HTML Document Path:</modernskydrive/product/skydrive/App.html>, Source File Name:<ms-appx://microsoft.microsoftskydrive/jx/jx.js>, Source Line Number:<1>, Source Column Number:<27246>, and Stack Trace: ms-appx://microsoft.microsoftskydrive/jx/jx.js:1:27246 localSettings() ms-appx://microsoft.microsoftskydrive/jx/jx.js:1:51544 _initSettings() ms-appx://microsoft.microsoftskydrive/jx/jx.js:1:54710 getApplicationStatus(boolean) ms-appx://microsoft.microsoftskydrive/jx/jx.js:1:48180 init(object) ms-appx://microsoft.microsoftskydrive/jx/jx.js:1:45583 Application(number, boolean) ms-appx://microsoft.microsoftskydrive/modernskydrive/product/skydrive/App.html:216:13 Anonymous function(object) Using ProcMon, I see a lot of access denied messages, like these: Date & Time: 12-9-2012 9:32:20 Event Class: File System Operation: CreateFile Result: ACCESS DENIED Path: D:\Users\John\AppData\Local\Packages\microsoft.microsoftskydrive_8wekyb3d8bbwe\Settings\settings.dat TID: 2520 Duration: 0.0000149 Desired Access: Read Data/List Directory, Write Data/Add File, Read Control Disposition: OpenIf Options: Sequential Access, Synchronous IO Non-Alert, No Compression Attributes: N ShareMode: None AllocationSize: 0 Any idea how to solve this? I noticed that the app folders e.g.: D:\Users\john\AppData\Local\Packages\microsoft.microsoftskydrive_8wekyb3d8bbwe had a different owner than the old profile folder had. Old profile folder had john as owner where my new profile folder had the Administrators group as owner. Changing this didn't help unfortunately.

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  • Scaling databases with cheap SSD hard drives

    - by Dennis Kashkin
    Hey guys! I hope that many of you are working with high traffic database-driven websites, and chances are that your main scalability issues are in the database. I noticed a couple of things lately: Most large databases require a team of DBAs in order to scale. They constantly struggle with limitations of hard drives and end up with very expensive solutions (SANs or large RAIDs, frequent maintenance windows for defragging and repartitioning, etc.) The actual annual cost of maintaining such databases is in $100K-$1M range which is too steep for me :) Finally, we got several companies like Intel, Samsung, FusionIO, etc. that just started selling extremely fast yet affordable SSD hard drives based on SLC Flash technology. These drives are 100 times faster in random read/writes than the best spinning hard drives on the market (up to 50,000 random writes per second). Their seek time is pretty much zero, so the cost of random I/O is the same as sequential I/O, which is awesome for databases. These SSD drives cost around $10-$20 per gigabyte, and they are relatively small (64GB). So, there seems to be an opportunity to avoid the HUGE costs of scaling databases the traditional way by simply building a big enough RAID 5 array of SSD drives (which would cost only a few thousand dollars). Then we don't care if the database file is fragmented, and we can afford 100 times more disk writes per second without having to spread the database across 100 spindles. . Is anybody else interested in this? I've been testing a few SSD drives and can share my results. If anybody on this site has already solved their I/O bottleneck with SSDs, I would love to hear your war stories! PS. I know that there are plenty of expensive solutions out there that help with scalability, for example the time proven RAM-based SANs. I want to be clear that even $50K is too expensive for my project. I have to find a solution that costs no more than $10K and does not take much time to implement.

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  • High speed network configuration

    - by Peter M
    Sorry if this seems to be a stupid question, I'm not sure how to specify what I want to know when checking google. I will have 2 or 3 devices pumping out data on a 100Base-T port. The combined data rate of all devices is about 15KB/S which exceeds the optimal 100Base-T channel capacity (12KB/S), but well within the realms of a 1000Base-T connection. Each device will be sending a burst of data in the form of an FTP transfer to a common, single host computer in a sequential manner ie: Device A establishes FTP connection and transfers data Device B establishes FTP connection and transfers data Device C establishes FTP connection and transfers data It may be that the A&B, B&C and C&A transfers overlap in the time domain to some extent. There will be minimal traffic going back from the computer to each device (in general what ever is needed to support the FTP transfers), and the network will be dedicated to transferring data between these devices and the host computer. Is it possible to use a switch to combine the multiple incoming 100Base-T streams into a single outgoing 1000Base-T stream? if so what features in a switch should I be looking for? Or would it be better to have 3 physical point-to-point 100Base-T dedicated connections between each device and the host computer? (thus having at least 3 physical Ethernet interfaces on that computer) Note that I can't change the interface on the devices, but I am free to choose the network and host computer configuration. Thanks for you help Peter

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  • How to diagnose storage system scaling problems?

    - by Unknown
    We are currently testing the maximum sequential read throughput of a storage system (48 disks total behind two HP P2000 arrays) connected to HP DL580 G7 running RHEL 5 with 128 GB of memory. Initial testing has been mainly done by running DD-commands like this: dd if=/dev/mapper/mpath1 of=/dev/null bs=1M count=3000 In parallel for each disk. However, we have been unable to scale the results from one array (maximum throughput of 1.3 GB/s) to two (almost the same throughput). Each array is connected to a dedicated host bust adapter, so they should not be the bottleneck. The disks are currently in JBOD configuration, so each disk can be addressed directly. I have two questions: Is running multiple DD commands in parallel really a good way to test maximum read throughput? We have noticed very high SWAPIN-% numbers in iotop, which I find hard to explain because the target is /dev/null How shoud we proceed in trying to find the reason for the scaling problem? Do you thing the server itself is the bottleneck here, or could there be some linux parameters that we have overlooked?

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  • To what extent is size a factor in SSD performance?

    - by artif
    To what extent is the size of an SSD a factor in its performance? In my mind, correct me if I'm wrong, a bigger SSD should be, everything else being equal, faster than a smaller one. A bigger SSD would have more erase blocks and thus more leeway for the FTL (flash translation layer) to do garbage collection optimization. Also there would be more time before TRIM became necessary. I see on Wikipedia that it remarks that "The performance of the SSD can scale with the number of parallel NAND flash chips used in the device" so it seems throughput also increases significantly. Also many SSDs contain internal caches of some sort and presumably those caches are larger for correspondingly large SSDs. But supposing this effect exists, I would like a quantitative analysis. Does throughput increase linearly? How much is garbage collection impacted, if at all? Does latency stay the same? And so on. Would the performance of a 8 GB SSD be significantly different from, for example, an 80 GB SSD assuming both used high quality chips, controllers, etc? Are there any resources (webpages, research papers, presentations, books, etc) that discuss correlations between SSD performance (4 KB random write speed, latency, maximum sequential throughput, etc) and size? I realize this does not really sound like a programming question but it is relevant for what I'm working on (using flash for caching hard drive data) which does involve programming. If there is a better place to ask this question, eg a more hardware oriented site, what would that be? Something like the equivalent of stack overflow (or perhaps a forum) for in-depth questions on hardware interfaces, internals, etc would be appreciated.

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  • How can use mod_rewrite to redirect a multiple specific URLs containing multiple query strings?

    - by Derek
    Hi there folks, we recently migrated a site from a custom CMS to drupal. In an effort to preserve some links that our users bookmarked (we have about 120 redirects) we would like to forward the original URLs to a new URL. I have been searching for a couple days, but can't seem to find anything simple to what I need. We have existing URLS that contain one or more query strings, for example: /article.php?issue_id=12&article_id=275 and we would like to forward to the new location: http://foobar.edu/content/super-happy-fun-article I started using: RewriteEngine On RewriteRule ^/article\.php?issue_id=12&article_id=275$ http://foobar.edu/content/super-happy-fun-article [R=301,L] This, however, does not work. A simple RewriteRule works: RewriteRule ^test\.php$ index.php It is unclear to me how I need to use {QUERY_STRING} with multiple Basically it's 120 simple redirects that go from one existing URL to a new one. I don't need ranges [0-9], because there is no sequential order to existing URLs. Perhaps I can do what I need with RewriteMap and a simple text file that contains a line like this: index.php?issue_id=12&articleType_section=0&articleType_id=65 http://foobar.edu/category/fall-2008 If anyone has any idea on using mod_rewrite to accomplish this or if there is a better, or more simple mod, I am open to that as well. Thanks!

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  • Nginx and 1000 WordPress Installs - Optimization

    - by GTE
    Hey, I'm trying to create a rather unusual (imo) configuration where I have: nginx php-fastcgi mysql 1000 seperate WordPress installs (with WP Super Cache). Each WP install corresponds to a seperate subdomain. Furthermore, I have 1000 cron jobs being called every hour that in turn call a WP plugin (using wget) which retrieves data from an API and posts it to the respective blog. This is all being run on a virtual server with 1024MB of RAM, 4 shared processors, etc. The server is not doing well, especially during the times that the cron jobs are being executed. Nginx constantly throws 504 errors and the site has a significant lag. 1) Am I crazy for having 1000 individual WP installs? Should I be using WP-MU and will this help significantly? (I have certain plugin restrictions that I prefer having seperate installs but could switch if need be.) 2) Instead of having 1000 unique cron jobs - should be calling say a bash script that will then process the 1000 HTTP requests I need? Could this be done in a succesive order instead of a sequential one? 3) Any other kind of suggestion you may have for optimization? Should I be proxying to Apache instead of just using nginx, etc. Any kind of advice would be appreciated. Thanks in advance

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  • Entry lvl. COBOL Control Breaks

    - by Kyle Benzle
    I'm working in COBOL with a double control break to print a hospital record. The input is one record per line, with, hospital info first, then patient info. There are multiple records per hospital, and multiple services per patient. The idea is, using a double control break, to print one hospital name, then all the patients from that hospital. Then print the patient name just once for all services, like the below. I'm having trouble with my output, and am hoping someone can help me get it in order. I am using AccuCobol to compile experts-exchange does not allow .cob and .dat so the extentions were changed to .txt The files are: the .cob lab5b.cob the input / output: lab5bin.dat, lab5bout.dat The assignment: http://www.cse.ohio-state.edu/~sgomori/314/lab5.html Hospital Number: 001 Hospital Name: Mount Carmel 00001 Griese, Brian Ear Infection 08/24/1999 300.00 Diaper Rash 09/05/1999 25.00 Frontal Labotomy 09/25/1999 25,000.00 Rear Labotomy 09/26/1999 25,000.00 Central Labotomy 09/28/1999 24,999.99 The total amount owed for this patient is: $.......... (End of Hospital) The total amount owed for this hospital is: $......... enter code here IDENTIFICATION DIVISION. PROGRAM-ID. LAB5B. ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT FILE-IN ASSIGN TO 'lab5bin.dat' ORGANIZATION IS LINE SEQUENTIAL. SELECT FILE-OUT ASSIGN TO 'lab5bout.dat' ORGANIZATION IS LINE SEQUENTIAL. DATA DIVISION. FILE SECTION. FD FILE-IN. 01 HOSPITAL-RECORD-IN. 05 HOSPITAL-NUMBER-IN PIC 999. 05 HOSPITAL-NAME-IN PIC X(20). 05 PATIENT-NUMBER-IN PIC 99999. 05 PATIENT-NAME-IN PIC X(20). 05 SERVICE-IN PIC X(30). 05 DATE-IN PIC 9(8). 05 OWED-IN PIC 9(7)V99. FD FILE-OUT. 01 REPORT-REC-OUT PIC X(100). WORKING-STORAGE SECTION. 01 WS-WORK-AREAS. 05 WS-HOLD-HOSPITAL-NUM PIC 999 VALUE ZEROS. 05 WS-HOLD-PATIENT-NUM PIC 99999 VALUE ZEROS. 05 ARE-THERE-MORE-RECORDS PIC XXX VALUE 'YES'. 88 MORE-RECORDS VALUE 'YES'. 88 NO-MORE-RECORDS VALUE 'NO '. 05 FIRST-RECORD PIC XXX VALUE 'YES'. 05 WS-PATIENT-TOTAL PIC 9(9)V99 VALUE ZEROS. 05 WS-HOSPITAL-TOTAL PIC 9(9)V99 VALUE ZEROS. 05 WS-PAGE-CTR PIC 99 VALUE ZEROS. 01 WS-DATE. 05 WS-YR PIC 9999. 05 WS-MO PIC 99. 05 WS-DAY PIC 99. 01 HL-HEADING1. 05 PIC X(49) VALUE SPACES. 05 PIC X(14) VALUE 'OHIO INSURANCE'. 05 PIC X(7) VALUE SPACES. 05 HL-PAGE PIC Z9. 05 PIC X(14) VALUE SPACES. 05 HL-DATE. 10 HL-MO PIC 99. 10 PIC X VALUE '/'. 10 HL-DAY PIC 99. 10 PIC X VALUE '/'. 10 HL-YR PIC X VALUE '/'. 01 HL-HEADING2. 05 PIC XXXXXXXXXX VALUE 'HOSPITAL: '. 05 HL-HOSPITAL PIC 999. 01 HL-HEADING3. 05 PIC X(7) VALUE "Patient". 05 PIC X(3) VALUE SPACES. 05 PIC X(7) VALUE "Patient". 05 PIC X(39) VALUE SPACES. 05 PIC X(7) VALUE "Date of". 05 PIC X(3) VALUE SPACES. 05 PIC X(6) VALUE "Amount". 01 HL-HEADING4. 05 PIC X(6) VALUE "Number". 05 PIC X(4) VALUE SPACES. 05 PIC X(4) VALUE "Name". 05 PIC X(18) VALUE SPACES. 05 PIC X(10) VALUE "Service". 05 PIC X(14) VALUE SPACES. 05 PIC X(8) VALUE "Service". 05 PIC X(2) VALUE SPACES. 05 PIC X(5) VALUE "Owed". 01 DL-PATIENT-LINE. 05 PIC X(28) VALUE SPACES. 05 DL-PATIENT-NUMBER PIC XXXXX. 05 PIC X(21) VALUE SPACES. 05 DL-PATIENT-TOTAL PIC $$$,$$$,$$9.99. 01 DL-HOSPITAL-LINE. 05 PIC X(47) VALUE SPACES. 05 PIC X(16) VALUE 'HOSPITAL TOTAL: '. 05 DL-HOSPITAL-TOTAL PIC $$$,$$$,$$9.99. PROCEDURE DIVISION. 100-MAIN-MODULE. PERFORM 600-INITIALIZATION-RTN PERFORM UNTIL NO-MORE-RECORDS READ FILE-IN AT END MOVE 'NO ' TO ARE-THERE-MORE-RECORDS NOT AT END PERFORM 200-DETAIL-RTN END-READ END-PERFORM PERFORM 400-HOSPITAL-BREAK PERFORM 700-END-OF-JOB-RTN STOP RUN. 200-DETAIL-RTN. EVALUATE TRUE WHEN FIRST-RECORD = 'YES' MOVE PATIENT-NUMBER-IN TO WS-HOLD-PATIENT-NUM MOVE HOSPITAL-NUMBER-IN TO WS-HOLD-HOSPITAL-NUM PERFORM 500-HEADING-RTN MOVE 'NO ' TO FIRST-RECORD WHEN HOSPITAL-NUMBER-IN NOT = WS-HOLD-HOSPITAL-NUM PERFORM 400-HOSPITAL-BREAK WHEN PATIENT-NUMBER-IN NOT = WS-HOLD-PATIENT-NUM PERFORM 300-PATIENT-BREAK END-EVALUATE ADD OWED-IN TO WS-PATIENT-TOTAL. 300-PATIENT-BREAK. MOVE WS-PATIENT-TOTAL TO DL-PATIENT-TOTAL MOVE WS-HOLD-PATIENT-NUM TO DL-PATIENT-NUMBER WRITE REPORT-REC-OUT FROM DL-PATIENT-LINE AFTER ADVANCING 2 LINES ADD WS-PATIENT-TOTAL TO WS-HOSPITAL-TOTAL IF MORE-RECORDS MOVE ZEROS TO WS-PATIENT-TOTAL MOVE PATIENT-NUMBER-IN TO WS-HOLD-PATIENT-NUM END-IF. 400-HOSPITAL-BREAK. PERFORM 300-PATIENT-BREAK MOVE WS-HOSPITAL-TOTAL TO DL-HOSPITAL-TOTAL WRITE REPORT-REC-OUT FROM DL-HOSPITAL-LINE AFTER ADVANCING 2 LINES IF MORE-RECORDS MOVE ZEROS TO WS-HOSPITAL-TOTAL MOVE HOSPITAL-NUMBER-IN TO WS-HOLD-HOSPITAL-NUM PERFORM 500-HEADING-RTN END-IF. 500-HEADING-RTN. ADD 1 TO WS-PAGE-CTR MOVE WS-PAGE-CTR TO HL-PAGE MOVE WS-HOLD-HOSPITAL-NUM TO HL-HOSPITAL WRITE REPORT-REC-OUT FROM HL-HEADING1 AFTER ADVANCING PAGE WRITE REPORT-REC-OUT FROM HL-HEADING2 AFTER ADVANCING 2 LINES. WRITE REPORT-REC-OUT FROM HL-HEADING3 AFTER ADVANCING 2 LINES. 600-INITIALIZATION-RTN. OPEN INPUT FILE-IN OUTPUT FILE-OUT *159 ACCEPT WS-DATE FROM DATE YYYYMMDD MOVE WS-YR TO HL-YR MOVE WS-MO TO HL-MO MOVE WS-DAY TO HL-DAY. 700-END-OF-JOB-RTN. CLOSE FILE-IN FILE-OUT.

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  • Marshalling to a native library in C#

    - by Daniel Baulig
    I'm having trouble calling functions of a native library from within managed C# code. I am developing for the 3.5 compact framework (Windows Mobile 6.x) just in case this would make any difference. I am working with the waveIn* functions from coredll.dll (these are in winmm.dll in regular Windows I believe). This is what I came up with: // namespace winmm; class winmm [StructLayout(LayoutKind.Sequential)] public struct WAVEFORMAT { public ushort wFormatTag; public ushort nChannels; public uint nSamplesPerSec; public uint nAvgBytesPerSec; public ushort nBlockAlign; public ushort wBitsPerSample; public ushort cbSize; } [StructLayout(LayoutKind.Sequential)] public struct WAVEHDR { public IntPtr lpData; public uint dwBufferLength; public uint dwBytesRecorded; public IntPtr dwUser; public uint dwFlags; public uint dwLoops; public IntPtr lpNext; public IntPtr reserved; } public delegate void AudioRecordingDelegate(IntPtr deviceHandle, uint message, IntPtr instance, ref WAVEHDR wavehdr, IntPtr reserved2); [DllImport("coredll.dll")] public static extern int waveInAddBuffer(IntPtr hWaveIn, ref WAVEHDR lpWaveHdr, uint cWaveHdrSize); [DllImport("coredll.dll")] public static extern int waveInPrepareHeader(IntPtr hWaveIn, ref WAVEHDR lpWaveHdr, uint Size); [DllImport("coredll.dll")] public static extern int waveInStart(IntPtr hWaveIn); // some other class private WinMM.WinMM.AudioRecordingDelegate waveIn; private IntPtr handle; private uint bufferLength; private void setupBuffer() { byte[] buffer = new byte[bufferLength]; GCHandle bufferPin = GCHandle.Alloc(buffer, GCHandleType.Pinned); WinMM.WinMM.WAVEHDR hdr = new WinMM.WinMM.WAVEHDR(); hdr.lpData = bufferPin.AddrOfPinnedObject(); hdr.dwBufferLength = this.bufferLength; hdr.dwFlags = 0; int i = WinMM.WinMM.waveInPrepareHeader(this.handle, ref hdr, Convert.ToUInt32(Marshal.SizeOf(hdr))); if (i != WinMM.WinMM.MMSYSERR_NOERROR) { this.Text = "Error: waveInPrepare"; return; } i = WinMM.WinMM.waveInAddBuffer(this.handle, ref hdr, Convert.ToUInt32(Marshal.SizeOf(hdr))); if (i != WinMM.WinMM.MMSYSERR_NOERROR) { this.Text = "Error: waveInAddrBuffer"; return; } } private void setupWaveIn() { WinMM.WinMM.WAVEFORMAT format = new WinMM.WinMM.WAVEFORMAT(); format.wFormatTag = WinMM.WinMM.WAVE_FORMAT_PCM; format.nChannels = 1; format.nSamplesPerSec = 8000; format.wBitsPerSample = 8; format.nBlockAlign = Convert.ToUInt16(format.nChannels * format.wBitsPerSample); format.nAvgBytesPerSec = format.nSamplesPerSec * format.nBlockAlign; this.bufferLength = format.nAvgBytesPerSec; format.cbSize = 0; int i = WinMM.WinMM.waveInOpen(out this.handle, WinMM.WinMM.WAVE_MAPPER, ref format, Marshal.GetFunctionPointerForDelegate(waveIn), 0, WinMM.WinMM.CALLBACK_FUNCTION); if (i != WinMM.WinMM.MMSYSERR_NOERROR) { this.Text = "Error: waveInOpen"; return; } setupBuffer(); WinMM.WinMM.waveInStart(this.handle); } I read alot about marshalling the last few days, nevertheless I do not get this code working. When my callback function is called (waveIn) when the buffer is full, the hdr structure passed back in wavehdr is obviously corrupted. Here is an examlpe of how the structure looks like at that point: - wavehdr {WinMM.WinMM.WAVEHDR} WinMM.WinMM.WAVEHDR dwBufferLength 0x19904c00 uint dwBytesRecorded 0x0000fa00 uint dwFlags 0x00000003 uint dwLoops 0x1990f6a4 uint + dwUser 0x00000000 System.IntPtr + lpData 0x00000000 System.IntPtr + lpNext 0x00000000 System.IntPtr + reserved 0x7c07c9a0 System.IntPtr This obiously is not what I expected to get passed. I am clearly concerned about the order of the fields in the view. I do not know if Visual Studio .NET cares about actual memory order when displaying the record in the "local"-view, but they are obviously not displayed in the order I speciefied in the struct. Then theres no data pointer and the bufferLength field is far to high. Interestingly the bytesRecorded field is exactly 64000 - bufferLength and bytesRecorded I'd expect both to be 64000 though. I do not know what exactly is going wrong, maybe someone can help me out on this. I'm an absolute noob to managed code programming and marshalling so please don't be too harsh to me for all the stupid things I've propably done. Oh here's the C code definition for WAVEHDR which I found here, I believe I might have done something wrong in the C# struct definition: /* wave data block header */ typedef struct wavehdr_tag { LPSTR lpData; /* pointer to locked data buffer */ DWORD dwBufferLength; /* length of data buffer */ DWORD dwBytesRecorded; /* used for input only */ DWORD_PTR dwUser; /* for client's use */ DWORD dwFlags; /* assorted flags (see defines) */ DWORD dwLoops; /* loop control counter */ struct wavehdr_tag FAR *lpNext; /* reserved for driver */ DWORD_PTR reserved; /* reserved for driver */ } WAVEHDR, *PWAVEHDR, NEAR *NPWAVEHDR, FAR *LPWAVEHDR; If you are used to work with all those low level tools like pointer-arithmetic, casts, etc starting writing managed code is a pain in the ass. It's like trying to learn how to swim with your hands tied on your back. Some things I tried (to no effect): .NET compact framework does not seem to support the Pack = 2^x directive in [StructLayout]. I tried [StructLayout(LayoutKind.Explicit)] and used 4 bytes and 8 bytes alignment. 4 bytes alignmentgave me the same result as the above code and 8 bytes alignment only made things worse - but that's what I expected. Interestingly if I move the code from setupBuffer into the setupWaveIn and do not declare the GCHandle in the context of the class but in a local context of setupWaveIn the struct returned by the callback function does not seem to be corrupted. I am not sure however why this is the case and how I can use this knowledge to fix my code. I'd really appreciate any good links on marshalling, calling unmanaged code from C#, etc. Then I'd be very happy if someone could point out my mistakes. What am I doing wrong? Why do I not get what I'd expect.

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  • Using Alarmmanager to start a service at specific time

    - by Javadid
    Hi friends, I have searched a lot of places but couldnt find a clean sequential explanation of how to start a service (or if thats not possible then an activity) at a specific time daily using the AlarmManager?? I want to register several such alarms and triggering them should result in a service to be started. I'll be having a small piece of code in the service which can then execute and i can finish the service for good.... Calendar cal = Calendar.getInstance(); Calendar cur_cal = Calendar.getInstance(); cur_cal.setTimeInMillis(System.currentTimeMillis()); Date date = new Date(cur_cal.get(Calendar.YEAR), cur_cal.get(Calendar.MONTH), cur_cal.get(Calendar.DATE), 16, 45); cal.setTime(date); Intent intent = new Intent(ProfileList.this, ActivateOnTime.class); intent.putExtra("profile_id", 2); PendingIntent pintent = PendingIntent.getService(ProfileList.this, 0, intent, 0); AlarmManager alarm = (AlarmManager)getSystemService(Context.ALARM_SERVICE); alarm.set(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), pintent); System.out.println("The alarm set!!"); i tried this code to activate the alarm at 4.45... but its not firing the service... do i have to keep the process running?? M i doing anything wrong??? One more thing, my service gets perfectly executed in case i use the following code: long firstTime = SystemClock.elapsedRealtime(); alarm.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, firstTime, 30*1000,pintent);

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  • C# CreatePipe() -> Protected memory error

    - by M. Dimitri
    Hi all, I trying to create a pipe using C#. The code is quite simple but I get a error saying "Attempted to read or write protected memory. This is often an indication that other memory is corrupt." Here the COMPLETE code of my form : public partial class Form1 : Form { [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)] public static extern bool CreatePipe(out SafeFileHandle hReadPipe, out SafeFileHandle hWritePipe, SECURITY_ATTRIBUTES lpPipeAttributes, int nSize); [StructLayout(LayoutKind.Sequential)] public struct SECURITY_ATTRIBUTES { public DWORD nLength; public IntPtr lpSecurityDescriptor; public bool bInheritHandle; } public Form1() { InitializeComponent(); } private void btCreate_Click(object sender, EventArgs e) { SECURITY_ATTRIBUTES sa = new SECURITY_ATTRIBUTES(); sa.nLength = (DWORD)System.Runtime.InteropServices.Marshal.SizeOf(sa); sa.lpSecurityDescriptor = IntPtr.Zero; sa.bInheritHandle = true; SafeFileHandle hWrite = null; SafeFileHandle hRead = null; if (CreatePipe(out hRead, out hWrite, sa, 4096)) { MessageBox.Show("Pipe created !"); } else MessageBox.Show("Error : Pipe not created !"); } } At the top I declare : using DWORD = System.UInt32; Thank you very much if someone can help.

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  • Database Change Management - Setup for Initial Create Scripts, Subsequent Migration Scripts

    - by Martin Aatmaa
    I've got a database change management workflow in place. It's based on SQL scripts (so, it's not a managed code-based solution). The basic setup looks like this: Initial/ Generate Initial Schema.sql Generate Initial Required Data.sql Generate Initial Test Data.sql Migration 0001_MigrationScriptForChangeOne.sql 0002_MigrationScriptForChangeTwo.sql ... The process to spin up a database is to then run all the Initlal scripts, and then run the sequential Migration scripts. A tool takes case of the versioning requirements, etc. My question is, in this kind of setup, is it useful to also maintain this: Current/ Stored Procedures/ dbo.MyStoredProcedureCreateScript.sql ... Tables/ dbo.MyTableCreateScript.sql ... ... By "this" I mean a directory of scripts (separated by object type) that represents the create scripts for spinning up the current/latest version of the database. For some reason, I really like the idea, but I can't concretely justify it's need. Am I missing something? The advantages would be: For dev and source control, we would have the same object-per-file setup that we're used to For deployment, we can spin up a new DB instance to the latest version either by running the Initial+Migrate, or by running the scripts from Current/ For dev, we do not need a DB instance running in order to do development. We can do "offline" development on the Current/ folder. The disadvantages would be: For each change, we need to update the scripts in the Current/ folder, as well as create a Migration script (in the Migration/ folder) Thanks in advance for any input!

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