Is my RAID degraded or not?

ppshay

I have 4 x 2TB Sata drives in a CentOS box for backups.

In Webmin when I go to Hardware > Linux RAID, /dev/md0 and md1 is showing a failed disk but /dev/md2 is not - as per the screenshots.

I don't know a lot about Linux and wondering why this is happening.

Tillotson

Looks like one of your disks have failed. You'll need to identify which disk and replace. Hopefully you have labelled your disks :P

You can tell which disk is faulty from the shell:

[root@brain /]# mdadm --detail /dev/md0
/dev/md0:
        Version : 1.2
  Creation Time : Fri Sep  7 18:51:08 2012
     Raid Level : raid5
     Array Size : 5860268032 (5588.79 GiB 6000.91 GB)
  Used Dev Size : 2930134016 (2794.39 GiB 3000.46 GB)
   Raid Devices : 3
  Total Devices : 3
    Persistence : Superblock is persistent

    Update Time : Sat Dec 29 20:15:46 2012
          State : clean, degraded
 Active Devices : 2
Working Devices : 2
 Failed Devices : 1
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 512K

           Name : brain:0  (local to host brain)
           UUID : 3111f917:ed9f2461:e469efed:9b4a1881
         Events : 274

    Number   Major   Minor   RaidDevice State
       4       8        1        0      active sync   /dev/sda1
       1       8       17        1      active sync   /dev/sdb1
       2       0        0        2      removed

       3       8       33        -      faulty   /dev/sdc1

ppshay

Thanks. Any idea why two logical drives show a failure and one (the main data drive) doesn't?

I was getting failures on MD2 on previous occaisions so I removed the drive from the RAID (software) and re-added and rebuilt and it would be ok again for a couple of months. I will get a RAID card and see if that works better.