Joys of spare disks!

Robin Bowes <robin-lists@xxxxxxxxxxxxxx> · Mon, 28 Feb 2005 14:24:48 +0000

Hi,

I run a RAID5 array built from six 250GB Maxtor Maxline II SATA disks. 
After having several problems with Maxtor disks I decided to use a spare 
disk, i.e. 5+1 spare.

Well, *another* disk failed last week. The spare disk was brought into 
play seamlessly:

[root@dude ~]# mdadm --detail /dev/md5
/dev/md5:
        Version : 00.90.01
  Creation Time : Thu Jul 29 21:41:38 2004
     Raid Level : raid5
     Array Size : 974566400 (929.42 GiB 997.96 GB)
    Device Size : 243641600 (232.35 GiB 249.49 GB)
   Raid Devices : 5
  Total Devices : 6
Preferred Minor : 5
    Persistence : Superblock is persistent

    Update Time : Mon Feb 28 14:00:54 2005
          State : clean
 Active Devices : 5
Working Devices : 5
 Failed Devices : 1
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 128K

           UUID : a4bbcd09:5e178c5b:3bf8bd45:8c31d2a1
         Events : 0.6941488

    Number   Major   Minor   RaidDevice State
       0       8        2        0      active sync   /dev/sda2
       1       8       18        1      active sync   /dev/sdb2
       2       8       34        2      active sync   /dev/sdc2
       3       8       82        3      active sync   /dev/sdf2
       4       8       66        4      active sync   /dev/sde2

       5       8       50        -      faulty   /dev/sdd2

I've done a quick test of /dev/sdd2:

[root@dude ~]# dd if=/dev/sdd2 of=/dev/null bs=64k
dd: reading `/dev/sdd2': Input/output error
50921+1 records in
50921+1 records out

So, I guess it's time to raise another return with Maxtor <sigh>.

/dev/sdd1 is used in /dev/md0. So, just to confirm, is this what I need 
to do to remove bad disk/add new disk:

Remove faulty partition:

	mdadm --manage /dev/md5 --remove /dev/sdd2

Remove "good" from RAID1 array:

	mdadm --manage /dev/md0 --fail /dev/sdd1
	mdadm --manage /dev/md0 --remove /dev/sdd1

[pull out bad disk, install replacement]

Partition new disk (will be /dev/sdd) (All six disks are partitioned the 
same):

	fdisk -l /dev/sda | fdisk /dev/sdd

(I seem to remember having a problem with this when I did it last time. 
Something about a bug in fdisk that won't partition brand new new disks 
correctly? Or was it sfdisk?)

Add new partitions to arrays:

	mdadm --manage /dev/md0 --add /dev/sdd1
	mdadm --manage /dev/md5 --add /dev/sdd2

Thanks,

R.
--
http://robinbowes.com

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