Difference between revisions of "Replacing all drives in a Terastation Live"

From NAS-Central Buffalo - The Linkstation Wiki
Jump to: navigation, search
 
m (1 revision(s))

Revision as of 23:28, 10 November 2007

This manual describes step by step the replacment of all drives in a Terastation Live. It can eventually applied also to other Terastations. The requirements are only a RAID-System based on mdadm and a XFS file system.

Contents

Setup

Buffalo Terastation comprising 4x Samsung SP2504C 250GB SATA-II

New drives: 4x Samsung HD501LJ 500GB SATA-II

Neccessary tools

  • mdadm
  • xfs_growfs
  • fdisk

We often start with a full array as shown here by "df command"

root@DATEN:~# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/md1                481.6M    306.9M    174.7M  64% /
/dev/ram1                15.0M    116.0k     14.9M   1% /mnt/ram
/dev/md0                281.0M     15.0M    265.9M   5% /boot
/dev/md2                695.6G    631.4G     64.2G  91% /mnt/array1

and obviously we like to enlarge the array with out any backup which is very time consuming and we often do not have an appropriate backup device to store several hundred Gigabytes.

Replace drives

  • Shut the Terastation down via webinterface, command line or power button
  • Start with the 4th drive, remove it and replace it with another disc of same size or bigger (you can follow the instructions from the Buffalo Terastation manual.
  • Start the Terastation and it will show you a failed drive - don't panic :-)
  • Now you have to gain root console access via telnet or ssh, do not try to repair the raids from the webinterface
  • Take a look at the partition table of a working hard drive like /dev/sda
fdisk -l /dev/sda
 
Disk /dev/sda: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1          37      297171   83  Linux
/dev/sda2              38          99      498015   83  Linux
/dev/sda4             100       30401   243400815    5  Extended
/dev/sda5             100         116      136521   82  Linux swap
/dev/sda6             117       30390   243175873+  83  Linux
  • Start to create the identical partition table using fdisk on the new inserted drive /dev/sdd with fdisk /dev/sdd - Important - If you insert a bigger drive, then you would extend the size of the extended partition as well as partition 6 to the available maximum

Disk /dev/sdd: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1          37      297171   83  Linux
/dev/sdd2              38          99      498015   83  Linux
/dev/sdd4             100       60801   487588815    5  Extended
/dev/sdd5             100         116      136521   82  Linux swap
/dev/sdd6             117       60801   487452231   83  Linux
  • don't forget to specify the partition type of partition 5 as Linux Swap (82)
  • apply mkswap to the fifth partition
mkswap /dev/sdd5
  • now rebuild all three raids (0-2), the steps are a follows
mdadm -a /dev/md0 /dev/sdd1
mdadm -a /dev/md1 /dev/sdd2
mdadm -a /dev/md2 /dev/sdd6
  • now you can check if this was done correctly with
root@daten# mdadm --detail /dev/md0

/dev/md0:
        Version : 00.90.03
  Creation Time : Wed Jun 13 15:47:40 2007
     Raid Level : raid1
     Array Size : 297088 (290.17 MiB 304.22 MB)
    Device Size : 297088 (290.17 MiB 304.22 MB)
   Raid Devices : 4
  Total Devices : 4
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Tue Oct 30 07:39:29 2007
          State : clean
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0

           UUID : ec67ebdb:01b029ce:000bb777:9d5fd144
         Events : 0.730

    Number   Major   Minor   RaidDevice State
       0       8        1        0      active sync   /dev/sda1
       1       8       17        1      active sync   /dev/sdb1
       2       8       33        2      active sync   /dev/sdc1
       3       8       49        3      active sync   /dev/sdd1
  • The rebuild of array 0 and 1 runs quickly, but the large array takes a while (the web interface gives you an approximination for the rebuild time. It is usually more than 3-4 hours.
  • Important - do not replace a further drive until the rebuild is done.
  • repeat all these steps, including the shutdown and restart for all drives

Growing the array and file system

  • After all drives are replaced and the rebuild finished you can grow you array using
  mdadm --grow /dev/md2 -z max
  • the array daemon starts a resync subsequently after growing the array
root@DATEN:~# mdadm --detail /dev/md2
/dev/md2:
        Version : 00.90.03
  Creation Time : Wed Jun 13 08:29:22 2007
     Raid Level : raid5
     Array Size : 1462356480 (1394.61 GiB 1497.45 GB)
    Device Size : 487452160 (464.87 GiB 499.15 GB)
   Raid Devices : 4
  Total Devices : 4
Preferred Minor : 2
    Persistence : Superblock is persistent

    Update Time : Wed Oct 31 08:36:13 2007
          State : active, resyncing
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

 Rebuild Status : 50% complete

           UUID : 05c76307:69dff621:a11d513a:e4478523
         Events : 0.1320002

    Number   Major   Minor   RaidDevice State
       0       8        6        0      active sync   /dev/sda6
       1       8       22        1      active sync   /dev/sdb6
       2       8       38        2      active sync   /dev/sdc6
       3       8       54        3      active sync   /dev/sdd6
  • this step again takes about 5 hours
  • the last step is growing the file system which runs very quick, just run
xfs_growfs /mnt/array1/
  • and you can do that before the resync finished.
  • so we and up with a enlarged array without any data loss or backup :-)
root@DATEN:~# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/md1                481.6M    307.0M    174.6M  64% /
/dev/ram1                15.0M    116.0k     14.9M   1% /mnt/ram
/dev/md0                281.0M     15.0M    265.9M   5% /boot
/dev/md2                  1.4T    631.4G    763.1G  45% /mnt/array1
  • you can watch the progress by using the web interface or looking into /proc/mdstat
root@DATEN:~# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid5] [raid4]
md2 : active raid5 sda6[0] sdb6[1] sdd6[3] sdc6[2]
      1462356480 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]
      [============>........]  resync = 64.8% (315880576/487452160) finish=191.9min speed=14865K/sec

md1 : active raid1 sda2[0] sdb2[1] sdd2[3] sdc2[2]
      497920 blocks [4/4] [UUUU]

md0 : active raid1 sda1[0] sdb1[1] sdd1[3] sdc1[2]
      297088 blocks [4/4] [UUUU]

unused devices: <none>

Links