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• Is wiper.sh working?

  - by Aleksander Blomskøld

  I'm setting up a server running Ubuntu Precise, and I'm trying to verify if SSD TRIM is working. fstrim is failing: ~ sudo fstrim -v / fstrim: /: FITRIM ioctl failed: Operation not supported So I tried wiper.sh in hdparm: wiper-3.5 sudo ./wiper.sh --verbose --commit /dev/sda1 wiper.sh: Linux SATA SSD TRIM utility, version 3.5, by Mark Lord. rootdev=/dev/sda1 fsmode2: fsmode=read-write /: fstype=ext4 freesize = 169502088 KB, reserved = 1695020 KB Preparing for online TRIM of free space on /dev/sda1 (ext4 mounted read-write at /). This operation could silently destroy your data. Are you sure (y/N)? y Creating temporary file (167807068 KB).. Syncing disks.. Beginning TRIM operations.. get_trimlist=/sbin/hdparm --fibmap WIPER_TMPFILE.11503 /dev/sda: trimming 3211263 sectors from 64 ranges succeeded trimming 3571713 sectors from 64 ranges succeeded trimming 3915776 sectors from 64 ranges succeeded (...) trimming 3657913 sectors from 60 ranges succeeded Removing temporary file.. Syncing disks.. Done. It seems to be working, but I'm wondering if it really is. Are there any cases where wiper.sh should work when fstrim isn't? Is there any way I can check if the TRIMing actually has succeeded (other than trusting the wiper.sh-log)?

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• Degraded RAID-5 array with lvm2 lost superblock and partition table

  - by Fred Phillips

  I have a RAID-5 array of 4x1TB hard disks with one lvm2 partition on Ubuntu Linux 10.04 LTS. One of the disks has failed. I have re-assembled the array without this failed disk but now mdadm --examine claims the array has no superblock and fdisk says it has no partition table. What can I do to recover the data? # mdadm -D /dev/md0 /dev/md0: Version : 1.2 Creation Time : Sat Mar 5 14:43:49 2011 Raid Level : raid5 Array Size : 2930276352 (2794.53 GiB 3000.60 GB) Used Dev Size : 976758784 (931.51 GiB 1000.20 GB) Raid Devices : 4 Total Devices : 4 Persistence : Superblock is persistent Update Time : Sat Mar 5 15:06:49 2011 State : clean, degraded Active Devices : 3 Working Devices : 3 Failed Devices : 1 Spare Devices : 0 Layout : left-symmetric Chunk Size : 512K Name : boba:1 (local to host boba) UUID : 52eb4bc9:c3d8aab5:e0699505:e0e1aa05 Events : 18 Number Major Minor RaidDevice State 0 8 1 0 active sync /dev/sda1 1 8 65 1 active sync /dev/sde1 2 8 49 2 active sync /dev/sdd1 3 0 0 3 removed 4 8 17 - faulty spare /dev/sdb1 # mdadm --examine /dev/md0 mdadm: No md superblock detected on /dev/md0. # fdisk -l /dev/md0 Disk /dev/md0: 3000.6 GB, 3000602984448 bytes 2 heads, 4 sectors/track, 732569088 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 524288 bytes / 1572864 bytes Disk identifier: 0x00000000 Disk /dev/md0 doesn't contain a valid partition table # cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] [linear] [multipath] [raid0] [raid1] [raid10] md0 : active raid5 sdb1[4](F) sda1[0] sdd1[2] sde1[1] 2930276352 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [UUU_] unused devices: <none>

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• Adding third disk as a single disk in a server with an existing RAID1

  - by slowhandsolo

  I've got a ProLiant DL360 G5 server (Fedora 13) with two SAS disks in a hardware RAID 1, working fine. Now I hot plugged another SAS disk. I'd like to configure this new hard disk out of my RAID, as a single non-RAID disk (ex. /dev/sdb). Even after rebooting the server, I can't see the new disk with "fdisk -l". It displays only my hardware RAID, but not the new disk. [root@myserver]# fdisk -l Disco /dev/cciss/c0d0: 300.0 GB, 299966445568 bytes Disposit. Inicio Comienzo Fin Bloques Id Sistema /dev/cciss/c0d0p1 * 1 126 512000 83 Linux /dev/cciss/c0d0p2 126 71798 292422656 8e Linux LVM Disco /dev/dm-0: 234.9 GB, 234881024000 bytes Disco /dev/dm-1: 10.5 GB, 10536091648 bytes Disco /dev/dm-2: 21.0 GB, 20971520000 bytes Disco /dev/dm-3: 31.5 GB, 31474057216 bytes Disco /dev/dm-4: 1577 MB, 1577058304 bytes However, I can see the new disk using the HP Array Configuration Utility CLI for Linux "hpacucli": [root@myserver]# hpacucli => controller slot=0 physicaldrive all show status physicaldrive 1I:1:1 (port 1I:box 1:bay 1, 300 GB): OK physicaldrive 1I:1:2 (port 1I:box 1:bay 2, 300 GB): OK physicaldrive 1I:1:3 (port 1I:box 1:bay 3, 300 GB): OK => controller slot=0 pd all show detail Smart Array P400i in Slot 0 (Embedded) array A physicaldrive 1I:1:1 Port: 1I Box: 1 Bay: 1 physicaldrive 1I:1:2 Port: 1I Box: 1 Bay: 2 **unassigned** physicaldrive 1I:1:3 Port: 1I Box: 1 Bay: 3 Status: OK Drive Type: **Unassigned Drive** As you can see, I've got two SAS disks in a RAID 1 and the new disk as "unassigned". Is there any way to work with the new disk as another non-RAID single disk? If relevant, I want to create a new partition in my new disk, format it with mkfs and mount it, but as I can't see it with fdisk, I don't know how to do it. Thanks!

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• Can I format a Veritas cluster shared volume from windows?

  - by spaghettidba

  We have a Microsoft Failover Cluster with dynamic disks managed by Veritas Storage Foundation. Today the sysadmins added a new disk for SQL Server but the cluster size on the volume was wrong, so I issued a quick format to change it. The disk volume failed, the SQL Server group failed as well and the cluster became unresponsive. After some minutes I managed to fail over to a passive node. The SAN admins say it's my fault because I shouldn't have formatted the disk from the Windows format applet, but I should have used Veritas Enterprise Administrator instead. Can a format operation bring offline a whole cluster group this way? Relevant error messages: From the eventlog: The cluster resource host subsystem (RHS) stopped unexpectedly. An attempt will be made to restart it. This is usually due to a problem in a resource DLL. Please determine which resource DLL is causing the issue and report the problem to the resource vendor. From the cluster.log ERR [RCM] rcm::RcmResControl::DoResourceControl: ERROR_RESOURCE_CALL_TIMED_OUT(5910)' because of 'Control(STORAGE_GET_DISK_INFO_EX) to resource 'NameOfTheDiskGroup' timed out.' Veritas Documentation: Excerpt from Symantec's documentation: Note: Before manually creating the resource, you must format the cluster-shared volume with NTFS using the VEA GUI and mount it on the node where you are trying to create the resource. Does this mean the disk cannot be formatted from Windows? I don't read it that way. For the record, I formatted many disks using the Windows applet in the past and nothing bad happened.

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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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• Why my internal hard disk can be ejected?

  - by Bear Bear

  I have 6 hard disks in my computer and one DVD. The disk that I connect to the 6th SATA port is a regular disk. But my Windows 7 64 bit shows it as a removable drive. I can eject my hard disk! Just like a pen drive. If I connect another disk to the 6th port, I can eject that disk too. So it has nothing to do with the physical disk, it must be something related to Windows or BIOS I don't understand why Windows 7 is seeing a normal hard disk as removable. In Computer Management - Disk Management, the disk looks identical to the others - there is nothing there to suggest the drive is different from the others. But in the tray I have the icon to eject it. The motherboard model is ASUS F2A85 V PRO FM2. All the disks are formatted normally, no Dynamic Disk, no RAID, nothing special. How can I tell Windows 7 to treat the disk exactly like the others, so it can't be ejected?

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• Sparing level on HP EVA 4000

  - by Samuel

  One of the disks of our EVA4000 died today. This diskgroup (all volumes vraid5 with sparing level 1 and almost no space left for more volumes, 1TiB drives) is being rebuilt with "spare space" right now, and it will take at least 15 hours to do the leveling/rebuilding. We can't get a new disk until Friday. So, the question is, what would happen if another disk dies before the leveling completes? Would we lose data? And after that, how many aditional disks could die before losing data? 1 or 2? In "usual" RAID, we would be vulnerable to data loss while the rebuild takes place, but in this case the space reserved for sparing is two times the size of the bigger disk, so at the very least the effect should be the same of having two spares. Thanks in advance. Update: I have found some interesting threads about this question but still can't answer to this question, so I'm starting a bounty. http://blog.thestoragearchitect.com/2008/10/27/understanding-eva/ http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&url=http%3A%2F%2Fwww.experts-exchange.com%2FStorage%2FStorage_Technology%2FQ_25548177.html (Expert Exchange question from google).

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• SBD killing both cluster nodes when there are even small SAN network problems

  - by Wieslaw Herr

  I am having problems with stonith SBD in a openais-based cluster. Some background: The active/passive cluster has two nodes, node1 and node2. They are configured to provide an NFS service to users. To avoid problems with split-brain, they are both configured to use SBD. SBD is using two 1MB disks available to the hosts via an multipath fibre-channel network. The problems start if something happens with the SAN network. For example, today one of the brocade switches got rebooted and both nodes lost 2 out of 4 paths to each disks, which resulted in both nodes committing suicide and rebooting. This, of course, was highly undesirable because a) there were paths left b) even if the switch would be out for 10-20 seconds a reboot cycle of both nodes would take 5-10 minutes and all NFS-locks would be lost. I tried increasing the SBD timeout values (to 10sec+ values, dump attached at the end), however a "WARN: Latency: No liveness for 4 s exceeds threshold of 3 s" hints that something isn't working as I would it expect to. Here is what I would like to know: a) Is SBD working as it should killing nodes when 2 paths are available? b) If not, is the multipath.conf file attached correct? The storage controller we use is an IBM SVC (IBM 2145), should there be any specific configuration for it? (as in multipath.conf.defaults) c) How should I go about increasing the timeouts in SBD attachements: Multipath.conf and sbd dump (http://hpaste.org/69537)

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• lvm mirroring space unavailable.

  - by Bryan Ward

  I am trying to migrate my data on lvm to two new disks, and setup mirroring between the two. I have successfully migrated all of the data to the first of the two disks, leaving the second one completely available as a mirror. I verified this using pvdisplay -m /dev/sd{g,h}1 --- Physical volume --- PV Name /dev/sdg1 VG Name vg PV Size 931.51 GiB / not usable 3.19 MiB Allocatable yes PE Size 4.00 MiB Total PE 238466 Free PE 82866 Allocated PE 155600 PV UUID v2nc3j-EFBR-QpuG-xgro-Rm59-fmu6-IB3QcR --- Physical Segments --- Physical extent 0 to 49999: Logical volume /dev/vg/videos Logical extents 0 to 49999 Physical extent 50000 to 99999: Logical volume /dev/vg/home Logical extents 0 to 49999 Physical extent 100000 to 129999: Logical volume /dev/vg/music Logical extents 0 to 29999 Physical extent 130000 to 155599: Logical volume /dev/vg/videos Logical extents 50000 to 75599 Physical extent 155600 to 238465: FREE --- Physical volume --- PV Name /dev/sdh1 VG Name vg PV Size 931.51 GiB / not usable 3.19 MiB Allocatable yes PE Size 4.00 MiB Total PE 238466 Free PE 238466 Allocated PE 0 PV UUID LuTrem-WcsZ-qw7l-2CDS-lLKI-wdq0-QEXhLf --- Physical Segments --- Physical extent 0 to 238465: FREE Then when I try to mirror the home logical volume for example, it says that I do not have sufficient space. I used lvconvert -m1 vg/home and the output was: Insufficient suitable allocatable extents for logical volume : 50000 more required Unable to allocate extents for mirror(s). This puzzling to me because it appears as if there is plenty of space on the second disk to mirror. Is there something I have done wrong here? Or is there a way to explicitly tell LVM where to put each leg of the mirror? I'm using lvm2.

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• Which upgrade path for disk IO bound postgres server?

  - by user41679

  Hi all, We currently have a Sun x4270 with 2xquad core Xeon Nehalmen 2.93ghz cores (16 threads), 72 gig of ram and 16 x 10k SAS disks split between the os raid 1, a partition for the Write Ahead Logs which is raid 10 and a partition for the database tables and indexes which is also raid 10, all xfs. I'm currently evaluating which path to go down in terms of upgrades. We'll be sharding the DB at some point soon, but for now I need to focus on hardware upgrades specifically. The machine is not CPU or memory bound at all at the moment, just IOWait is become an issue. The machine is mostly write access as we have a heavy caching layer. We're seeing about 300 write IOPS average on both the database partitions. We don't have any additional storage infrastructure like a Fiber Channel or ISCSI network. Budget isn't too much of a concern, something inline with the size of this server (i.e no $1m IBM machines) Space is ok on the DB side of things, we're running out obviously but there's also some reduction we can do. Additional space would be good though. My current thoughts are either: * ISCSI SAN, possible with 10Gbit network that has solid state acceleration. * FusionIO card / Sun F20 card (will the FusionIO card work in the Sun box? * DAS shelf (something like this http://www.broadberry.co.uk/das-direct-attached-storage-servers/cyberstore-224s-das) which a combination of 15k sas disks and some Intel X25-E drives for DB indexes etc) what would I need to put in the x4270 to add a DAS shelf? I think it's a SAS HBA card, do I have to use Sun's own card or will any PCI Express card work? Anything else??? what would you guys do from your experience? I appreciate it's a lot of questions, but I haven't expanded a DB machine for a number of years and the landscape has changed dramatically since then! Any advice or feedback would be very much appreciated. Let me know if there's anything else I can clarify. Thanks in advance!

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• Raid-z unaccessible after putting one disk offline

  - by varesa

  I have installed FreeNAS on a test server, with 3x 1Tb drives. They are setup in raidz. I tried to offline one of the disks (from the FreeNAS web-ui), and the array became degraded, as I think it should. The problem is with the array becoming unaccessible after that. I thought a raid like that should be able to run fine with one of the disks missing. Atleast very soon after I offline'd and pulled out the disk, the iSCSI share disappeared from a ESXi host's datastores. I also ssh'd into the FreeNAS server, and tried just executing ls /mnt/raid (/mnt/raid/ being the mount point). The whole terminal froze, not accepting ^C or anything. # zpool status -v pool: raid state: DEGRADED status: One or more devices are faulted in response to IO failures. action: Make sure the affected devices are connected, then run 'zpool clear'. see: http://www.sun.com/msg/ZFS-8000-HC scrub: none requested config: NAME STATE READ WRITE CKSUM raid DEGRADED 1 30 0 raidz1 DEGRADED 4 56 0 gptid/c8c9e44c-08e1-11e2-9ba6-001b212a83ea ONLINE 3 60 0 gptid/c96f32d5-08e1-11e2-9ba6-001b212a83ea ONLINE 3 63 0 gptid/ca208205-08e1-11e2-9ba6-001b212a83ea OFFLINE 0 0 0 errors: Permanent errors have been detected in the following files: /mnt/raid/ raid/iscsivol:<0x0> raid/iscsivol:<0x1> Have I understood the workings of a raidz wrong, or is there something else going on? It would not be nice to have the same thing happen on a production system...

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• How to organise storage for media content such as video and music?

  - by thor

  Currently, we have a single server hosting all content: music, video and software. This content is downloaded by users through HTTP. Now free space is coming to an end and we are exploring different ways of extending our storage capacity. We want to do it cheap, simple and reliable (protected from disk/ server faults). Currenly, we see two ways: Add a couple of cheap servers with 4 disks (RAID1 ?), run some distributed file-system on top, like GlusterFS. Pros: hopefully, we will see all our disks as single flat file system, just dump content into it and be done. Cons: could be tricky in configuration and handling of faults. Add a couple of cheap servers, all running HTTP servers. Each piece of content (be it a music file or video) is placed on randomly selected two servers. Pros: don't have to deal with RAID, as content is duplicated; single server failure does not bring down any part of content; doubled distribution capacity (as any signle file could be downloaded from any of two servers hosting it). Cons: requires some scripting on part of distribution of content, adding/ removing servers. Do we miss any other ways? Which of the aforementioned options seems to be the best?

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• 2011 i7 Macbook Pro unable to boot from any Windows CD?

  - by Craig Otis

  I'm encountering issues installing Windows alongside my Lion install. I'm attempting to install from the internal SuperDrive, after using Boot Camp to partition what was a single, HFS+ volume. When holding down Option at boot, the CD appears in the startup list, but upon selecting it, I get a gray screen for 5 minutes, then a flashing white folder. I tried installing rEFIt and using this to boot the CD, but I receive an error about "Not Found" being returned from the "LocateDevicePath", and a mention of the firmware not supporting booting using legacy methods. In the Console, when opening the StartupDisk preference pane (which never presents the CD as a selectable option), I see: 11/25/11 4:39:31.159 PM System Preferences: isCDROM: 0 isDVDROM:1 11/25/11 4:39:31.159 PM System Preferences: mountable disk appeared: /Volumes/GRMCPRFRER_EN_DVD 11/25/11 4:39:33.214 PM System Preferences: - So far so good, passing disk to System Searcher. 11/25/11 4:39:33.218 PM System Preferences: OSXCheck: No boot.efi in System Folder or volume root. 11/25/11 4:39:33.220 PM System Preferences: WinCheck: Not a valid windows filesystem: /Volumes/GRMCPRFRER_EN_DVD 11/25/11 4:39:33.220 PM System Preferences: WinCheck: Not a valid windows filesystem: /Volumes/GRMCPRFRER_EN_DVD I'm at a loss here. I've done my research, but it sounds like most of the rEFIt errors of this nature are caused by installing from a thumbdrive, or an external drive. I'm using the internal SuperDrive. Also, I've tried this with two different disks: A Windows XP SP2 CD A Windows 7 x86 DVD Both are disks I've had around for years, and I've used them reliably in the past. The system is an early 2011 15" Macbook Pro, all firmware updates installed.

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• trouble shooting ntfs-loop-xen combination in wubi based grub of Ubuntu

  - by Registered User

  Here is a situation I installed Ubuntu on a laptop using Wubi in Windows 7 drive.*The laptop is not mine.*I have installed and things worked by now perfectly without any problem.We are trying to set up a Xen (virtualization)environment in this laptop. After setting up every thing cleanly.When I needed to boot with following grub entries menuentry "Xen Linux 2.6.32.27" { insmod ntfs set root='(hd0,2)' loopback loop0 /ubuntu/disks/root.disk set root=(loop0) multiboot /boot/xen.gz module /boot/vmlinuz-2.6.32.27 dummy=dummy root=/dev/sda2 loop=/ubuntu/disks/root.disk ro console=tty0 module /boot/initrd.img-2.6.32.27 } I got error file not found error unknown command 'multiboot' error unknown command 'module' error unknown command 'module' Now to dig this issue further I reboot the machine and go to grub command prompt and manually pass on each of the above parameters which you see in the grub entry when I reached grub> insmod multiboot then I got following message on screen error:file not found. It looks like this wubi+ grub setup has just enough modules to use loopback file on ntfs, but the ACTUAL /boot directory is on the loopback NOT ntfs (hd0,2). Therefore any attempt to read any files from (hd0,2) simply wont work, cause there's no file there.I need to use insmod multiboot and command multiboot and module which are available in grub on a normal install without Wubi.But since the laptop is not mine so I am not allowed to partition it and have to make it work in this situation only. While a normal Kernel is still booting? How can I get module multiboot in this Wubi based install.

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• mkfs Operation Takes Very Long on Linux Software Raid 5

  - by Elmar Weber

  I've set-up a Linux software raid level 5 consisting of 4 * 2 TB disks. The disk array was created with a 64k stripe size and no other configuration parameters. After the initial rebuild I tried to create a filesystem and this step takes very long (about half an hour or more). I tried to create an xfs and ext3 filesystem, both took a long time, with mkfs.ext3 I observed the following behaviour, which might be helpful: writing inode tables runs fast until it reaches 1053 (~ 1 second), then it writes about 50, waits for two seconds, then the next 50 are written (according to the console display) when I try to cancel the operation with Control+C it hangs for half a minute before it is really canceled The performance of the disks individually is very good, I've run bonnie++ on each one separately with write / read values of around 95 / 110MB/s. Even when I run bonnie++ on every drive in parallel the values are only reduced by about 10 MB. So I'm excluding hardware / I/O scheduling in general as a problem source. I tried different configuration parameters for stripe_cache_size and readahead size without success, but I don't think they are that relevant for the file system creation operation. The server details: Linux server 2.6.35-27-generic #48-Ubuntu SMP x86_64 GNU/Linux mdadm - v2.6.7.1 Does anyone has a suggestion on how to further debug this?

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• How ZFS handles online replacement in a RAID-Z (theoretical)

  - by Kevin

  This is a somewhat theoretical question about ZFS and RAID-Z. I'll use a three disk single-parity array as an example for clarity, but the problem can be extended to any number of disks and any parity. Suppose we have disks A, B, and C in the pool, and that it is clean. Suppose now that we physically add disk D with the intention of replacing disk C, and that disk C is still functioning correctly and is only being replaced out of preventive maintenance. Some admins might just yank C and install D, which is a little more organized as devices need not change IDs - however this does leave the array degraded temporarily and so for this example suppose we install D without offlining or removing C. Solaris docs indicate that we can replace a disk without first offlining it, using a command such as: zpool replace pool C D This should cause a resilvering onto D. Let us say that resilvering proceeds "downwards" along a "cursor." (I don't know the actual terminology used in the internal implementation.) Suppose now that midways through the resilvering, disk A fails. In theory, this should be recoverable, as above the cursor B and D contain sufficient parity and below the cursor B and C contain sufficient parity. However, whether or not this is actually recoverable depnds upon internal design decisions in ZFS which I am not aware of (and which the manual doesn't say in certain terms). If ZFS continues to send writes to C below the cursor, then we are fine. If, however, ZFS internally treats C as though it were gone, resilvering D only from parity between A and B and only writing A and B below the cursor, then we're toast. Some experimenting could answer this question but I was hoping maybe someone on here already knows which way ZFS handles this situation. Thank you in advance for any insight!

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• Move OS from RAID5 array to RAID 1 arrays

  - by Antoine

  I want to give a last boost to my old ProLiant ML350 G5 server which just needs to be reliable for a few more year only ! With a defined budget of about 1500$ (I do not have more), i plan to replace the CPU (+ adding a second one), the battery cache of my raid controller (E200i), double the RAM, and change all hard drives. I have 7 HDD (SAS 10krpm, 72Gb) + 1 spare in RAID5, and my system is all FULL (no empty tray, full disks). in my current RAID5 array, I have 2 partitions: - 1 OS partition, 20Gb - 1 data partition, 350 Gb I plan to replace these 8 disks with : - 2 x 300Gb SAS 15krpm in RAID 1 (= 1 partition for OS) - 2 x 2Tb SATA 7.2krpm in RAID 1 (= 1 partition for DATA) My biggest constraint is that I have only 01 day to upgrade my server. Therefore, I'm looking for cloning all my files (OS + data partition) to my new arrays, i.e : - the OS partition shall be cloned to the RAID1 "2x300Gb array" - the data partition shall be cloned to the RAID1 "2x2Tb array" My second problem is that I need to physically remove all the old hard drives before inserting the new ones. I'm running Windows Server 2003 R2, and even if MS support will expire soon, I cannot buy a new licence and spent time in configuration. Obviously, with 1500$, I cannot also buy a new server that I could start configuring from now ! Thought about ASR (NTBackup), but I have no floppy drive (and do not really want to invest in one !) Thought about a clonezilla clone, and read this interesting link : Windows Server 2003 - move C: partition to a new SAS disk , but i'm not so confident in using Clonezilla with RAID5. What should be the best option to quickly and easily (if possible!) "copy/paste" my OS (so no need to reinstall and reconfigure all) and DATA / programs / services, etc... ? Thanks for your comments

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• mkfs Operation Takes Very Long on Linux Software Raid 5

  - by Elmar Weber

  I've set-up a Linux software raid level 5 consisting of 4 * 2 TB disks. The disk array was created with a 64k stripe size and no other configuration parameters. After the initial rebuild I tried to create a filesystem and this step takes very long (about half an hour or more). I tried to create an xfs and ext3 filesystem, both took a long time, with mkfs.ext3 I observed the following behaviour, which might be helpful: writing inode tables runs fast until it reaches 1053 (~ 1 second), then it writes about 50, waits for two seconds, then the next 50 are written (according to the console display) when I try to cancel the operation with Control+C it hangs for half a minute before it is really canceled The performance of the disks individually is very good, I've run bonnie++ on each one separately with write / read values of around 95 / 110MB/s. Even when I run bonnie++ on every drive in parallel the values are only reduced by about 10 MB. So I'm excluding hardware / I/O scheduling in general as a problem source. I tried different configuration parameters for stripe_cache_size and readahead size without success, but I don't think they are that relevant for the file system creation operation. The server details: Linux server 2.6.35-27-generic #48-Ubuntu SMP x86_64 GNU/Linux mdadm - v2.6.7.1 Does anyone has a suggestion on how to further debug this?

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• Should I use "Raid 5 + spare" or "Raid 6"?

  - by Trevor Boyd Smith

  What is "Raid 5 + Spare" (excerpt from User Manual, Sect 4.17.2, P.54): RAID5+Spare: RAID 5+Spare is a RAID 5 array in which one disk is used as spare to rebuild the system as soon as a disk fails (Fig. 79). At least four disks are required. If one physical disk fails, the data remains available because it is read from the parity blocks. Data from a failed disk is rebuilt onto the hot spare disk. When a failed disk is replaced, the replacement becomes the new hot spare. No data is lost in the case of a single disk failure, but if a second disk fails before the system can rebuild data to the hot spare, all data in the array will be lost. What is "Raid 6" (excerpt from User Manual, Sect 4.17.2, P.54): RAID6: In RAID 6, data is striped across all disks (minimum of four) and a two parity blocks for each data block (p and q in Fig. 80) is written on the same stripe. If one physical disk fails, the data from the failed disk can be rebuilt onto a replacement disk. This Raid mode can support up to two disk failures with no data loss. RAID 6 provides for faster rebuilding of data from a failed disk. Both "Raid 5 + spare" and "Raid 6" are SO similar ... I can't tell the difference. When would "Raid 5 + Spare" be optimal? And when would "Raid 6" be optimal"? The manual dumbs down the different raid with 5 star ratings. "Raid 5 + Spare" only gets 4 stars but "Raid 6" gets 5 stars. If I were to blindly trust the manual I would conclude that "Raid 6" is always better. Is "Raid 6" always better?

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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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• Possible disk IO issue

  - by Tim Meers

  I've been trying to really figure out what my IOPS are on my DB server array and see if it's just too much. The array is four 72.6gb 15k rpm drives in RAID 5. To calculate IOPS for RAID 5 the following formula is used: (reads + (4 * Writes)) / Number of disks = total IOPS. The formula is from MSDN. I also want to calculate the Avg Queue Length but I'm not sure where they are getting the formula from, but i think it reads on that page as avg que length/number of disks = actual queue. To populate that formula I used the perfmon to gather the needed information. I came up with this, under normal production load: (873.982 + (4 * 28.999)) / 4 = 247.495. Also the disk queue lengh of 14.454/4 = 3.614. So to the question, am I wrong in thinking this array has a very high disk IO? Edit I got the chance to review it again this morning under normal/high load. This time with even bigger numbers and IOPS in excess of 600 for about 5 minutes then it died down again. But I also took a look at the Avg sec/Transfer, %Disk Time, and %Idle Time. These number were taken when the reads/writes per sec were only 332.997/17.999 respectively. %Disk Time: 219.436 %Idle Time: 0.300 Avg Disk Queue Length: 2.194 Avg Disk sec/Transfer: 0.006 Pages/sec: 2927.802 % Processor Time: 21.877 Edit (again) Looks like I have that issue solved. Thanks for the help. Also for a pretty slick parser I found this: http://pal.codeplex.com/ It works pretty well for breaking down the data into something usable.

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• How to reinstall bootloader after migration to SSD

  - by hijarian

  I must say, it was difficult to name this question. Basically, I need to properly reinstall the bootloader on my system, because I already have the working system disks for my OSes. The long story is this: I had the large slow HDD with Windows7 & Debian Wheezy dual-boot on it, perfectly bootable. Then, I ordered the SSD drive and prepared my system partitions to fit onto the much smaller SSD. I wanted the following schema: 128 GB Windows 24 GB / on Debian 86 GB /home on Debian Strange size for /home because there's no such thing as true 256GB disk drive. So, I've prepared such a partitions on my initial HDD and installed the new SSD and then I loaded the GParted live USB (can't remember now how it was really named), and then just copypasted the partitions from HDD to SSD. So, now I have the following partitions across the physical disks: SSD 128 GB copy of original Windows partition 24 GB copy of presumably Debian / 86 GB copy of presumably Debian /home HDD 128 GB Windows 24 GB / on Debian 86 GB /home on Debian ... several other partitions with non-system data ... And the behavior of the system right after the Ctrl+C, Ctrl+V in GParted was as follows: no GRUB, system boots right into the Windows on HDD. In BIOS settings are to boot from SSD first. I managed to create the Debian Testing installation USB and loaded it into the rescue mode, found that it identified my SSD as /dev/sda and installed the GRUB to the /dev/sda. Now my system loads the GRUB which lists both Windows and Debian. From HDD. So, I am now back into initial position. Please, how I should set up the GRUB so it'll load the OSes correctly from SSD? Should I fire up my Debian, fiddle with the GRUB's config and reinstall it again to the same place (at SSD)?

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• Can't find partition tab in disk utility osX ver. 10.6.8

  - by John W

  I just got a used Mac Book Pro. I created a new admin account and deleted the old one as well as one other user. This is an older late 2007 MBP... the osX upgrade to 10.6.8 was just performed. My Macintosh HD is showing up as Partition 2. I ran disk utility (not from install disk), but there was no partition tab. I have a 160GB drive with only 53GB of space left on it. Since I am the only user and have no files on the laptop yet, I don't understand why there is so little space left. Surely the OS can't use up over 100GB. I wanted to run disk utility to see if there were any recovery partitions or other partition left over from the previous owner that could be erased to make room for expanding the main partition. Unfortunately, there is no partition tab in disk utility. The documentation I have found on line states that this version of osX includes that utility. The osX disks I have are for an older version so I wasn't sure if they would be of any use in solving this problem. Also, I was afraid if using the disks, would I lose the little bit of data/apps that I have assembled. I would rather not do a fresh install and have to do all the updates again to achieve this. The previous owner had some apps that I don't want to lose as I would have to pay handsomely to get them back. Simply, if all the previous users data is backed up on here after deleting user is still taking up space on a recovery partition (that I can't see)... I need to locate it erase it and expand the primary partition to re-aquire disk space for my files. I am new to Mac, so please be as descriptive as possible. Thanks.

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• What hardware would I need (approx) to run ESXi server?

  - by mr.b

  Hi, I am considering to purchase off-the-shelf commodity hardware in order to build server that will host virtual machines using ESXi server. Intended purpose for this server is NOT mission critical tasks. It will have to run perhaps 20-50 Windows XP/Vista/7 virtual machines (in total, but closer to 20 figure). Each guest would have to have 1-2 GB of ram, and probably two-three times more disk space than guest OS needs with clean install and all updates applied (that would be around 6-8 GB for XP, and i believe closer to 10-15 for win7). Those guests will act as a test ground for a new product that is network management software, thus guests will idle most of their time once initially loaded, but if I give them some task to complete, they should be able to perform reasonably well. Now, from what I have learned... CPU is usually not much of an issue (6 cores would do it), memory should not be lacking, but doesn't have to be sum of all guests, because of overcommitment... That leads me to IO, which is, as it seems, the bottleneck. Since I have very little experience with ESXi (and ESX, too) server, I'd like to ask: How much memory could I save by overcommitment, and how does it affect performance? Is 6-core cpu enough to run above described system? Would it be possible to run entire server off two (or even one) SSD drives (to host system virtual disks, with few additional HDDs (2-3) in RAID 0 to be used as secondary storage? I read somewhere that ESXi allows having something like "master image", essentially virtual machine that is "deployed" many times, so that disk space can be saved by having only differences stored by specific guests, instead of copying around whole virtual disks. Is this true, and how can this help me? Are there any other things I need to take into consideration when building this off-the-shelf solution? I should probably mention here that I'm fully aware of issues like SPOF regarding power supply, raid 0, etc, but since it's only a testing ground and not a production system, it's not so important for me. Thanks, B.

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• Motherboard Dying? AHCI Drive Init and boot loop intermittent failure

  - by Adam Heath

  My computer is now intermittently failing to boot up. For the last couple of days, when I turn it on it hangs on "AHCI Drive Init...", and when powered off and on again, it booted up fine. Today, it did the same but failed in a few other ways too, seemingly at random: Hangs on "AHCI Drive Init..." Boot loop (after "AHCI Drive Init..." appears for a split second (no drives listed)) Black screen (after "AHCI Drive Init..." appears for a split second, a black screen with all fans still running) The interesting part is that the above is not affected by what drives are connected, or what to. I have tried both disks, each disk individually and no disks (along with trying the primary and secondary SATA controllers), none of this has any effect on what happens. After about 20+ attempts of different combinations, it suddenly decided it would boot up into Windows, and I hadn't touched anything for about 2 cycles. Motherboard: Gigabyte GA-870A-USB3 Processor: Amd Phoenom II x6 1090T RAM: 8GB Corsair 1600 Primary Disk: Plextor 128GB SSD Secondary Disk: Western Digital Black 1TB OS: Windows 8.1 Is this my motherboard dying? Or could something else be the cause? Thanks!

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