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I have a raid array with several drives marked as removed. I want to add them back in, but am not sure how to do so.

[root@tera2 ~]# mdadm --detail /dev/md3
/dev/md3:

        Version : 1.2
  Creation Time : Fri Nov 30 07:39:25 2012
     Raid Level : raid6
  Used Dev Size : 1940681216 (1850.78 GiB 1987.26 GB)
   Raid Devices : 5
  Total Devices : 2
    Persistence : Superblock is persistent

    Update Time : Tue Jan 20 10:05:05 2015
          State : active, FAILED, Not Started 
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 512K

           Name : tera2.domain.com:3  (local to host tera2.domain.com)
           UUID : 4346aaf9:032147b3:3dcfd39c:7b7cca2a
         Events : 1351799

    Number   Major   Minor   RaidDevice State
       0       0        0        0      removed
       1       8       21        1      active sync   /dev/sdb5
       2       8       33        2      active sync   /dev/sdc1
       3       0        0        3      removed
       4       0        0        4      removed

Thanks!

HopelessN00b
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CD Brian
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  • I was able to add them back in with mdadm --manage /dev/md0 --add /dev/sdb1 It is important to note, the drives were removed from the array due to a faulty backplane. Once the drives were moved to a new physical machine with direct sata cables to the motherboard, I was able to add the device partitions back to the md and recover data. – CD Brian Jan 22 '15 at 12:30

1 Answers1

2

You can't. See where it says FAILED? That means your data is gone. RAID 5 can only sustain one failed drive, and generally speaking, is evil and to be avoided as if it were radioactive.

Remember kids, only people who hate their data use RAID 5.

HopelessN00b
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  • what raid due you recommend? This is 7tb of data right now and we will be adding more. So based on that, what is your recommendation for raid level? – CD Brian Jan 22 '15 at 12:32