Find the answer to your Linux question:
Results 1 to 5 of 5
So at this point im an extremely worried about my array as i need them 4TB of data on it. So here's the story: Server was running all good but ...
Enjoy an ad free experience by logging in. Not a member yet? Register.
  1. #1
    Just Joined!
    Join Date
    Oct 2010
    Posts
    4

    Mdadm droped a drive in RAID5. Wont rebuild


    So at this point im an extremely worried about my array as i need them 4TB of data on it.

    So here's the story:

    Server was running all good but the memory usage was high from a memory leak in java. So i restarted the server. One of the hard drives decided to change drive letters so i had to re-add it to the raid5 array and rebuild it. All good. Log into the server again and it says one of the other drives in the array has been dropped. Odd? SMART says its fine and its still in linux working fine. Array goes down as it now has 2 dropped drives. Im not sure if it finished rebuilding or not as i wasnt really keeping an eye on it for 30hours.

    So now i have a RAID5 array with 2 removed drives and 2 spare drives that is for some reason saying it is the wrong size and wont rebuild.

    Details:

    MDADM RAID5 with an LVM ontop on it.

    RAID5 consists of 4 1.5tb drives. = 4.5TB

    For some reason it is reporting as 5.76TB or so and i dont know why.

    mdadm.conf:

    RAY /dev/md1 level=raid5 num-devices=4 metadata=00.90 UUID=44fc3622:cf99fe69:5d53fc14:f3cbdc1c devices=/dev/sde1,/dev/sdg1,/dev/sdh1,/dev/sdi1

    (i changed it to match the correct drive letter and rebooted the server but still no dice.


    /etc/mdadm/mdadm.conf
    RRAY /dev/md1 level=raid5 num-devices=4 UUID=44fc3622:cf99fe69:5d53fc14:f3cbdc1c


    All drives are working and none of them are faulty.

    Please help

  2. #2
    Just Joined!
    Join Date
    Oct 2010
    Posts
    4
    Number Major Minor RaidDevice State
    0 0 0 0 removed
    1 8 113 1 active sync /dev/sdh1
    2 8 129 2 active sync /dev/sdi1
    3 0 0 3 removed

    4 8 65 - spare /dev/sde1
    5 8 97 - spare /dev/sdg1

  3. #3
    Linux Guru coopstah13's Avatar
    Join Date
    Nov 2007
    Location
    NH, USA
    Posts
    3,149
    wait, raid5 only has one parity disk, meaning you can lose 1 disk and the raid can rebuild itself, if you had 4 disks set up and 4.5 tb available you were using raid5 as usual 3x1.5tb = 4.5tb, but if you lost a 2nd disk you're hosed, raid6 uses 2 parity disks and means you can lose 2 disks without losing data. if you had 2 spares, you would only have 3tb available

  4. $spacer_open
    $spacer_close
  5. #4
    Just Joined!
    Join Date
    Oct 2010
    Posts
    4
    yeah it should be 4.5tb and it was for months before this happened.

    I dont see why a dropped drive counts as needing to be rebuilt from. Its not like it has lost any data from it

  6. #5
    Linux Guru coopstah13's Avatar
    Join Date
    Nov 2007
    Location
    NH, USA
    Posts
    3,149
    because the extra drive in raid5 is for parity, the whole point is if a single drive fails you can recover the raid set

    if you lose 2 drives in a raid5 you lose the data, you have to rebuild the raid after a drive is dropped before another drive is dropped

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •