Adding a disk to raid 5

  • Hello I already have a raid 5 array of 4 6TB disk running
    trying to add 3 more disk, they appear as beeing spare ...

    how to set only one spare disk and get 2 more disk in the active array ?

  • As there is no information on how you did the above, you should be able to do this from the GUI, Raid Management select the array on the menu click grow, a dialog should display the drives available.


    You'll then need to resize the file system for the array, from the cli mdadm --grow /dev/md* (where * is your raid reference) --size=max

    Raid is not a backup! Would you go skydiving without a parachute?

  • As there is no information on how you did the above, you should be able to do this from the GUI, Raid Management select the array on the menu click grow, a dialog should display the drives available.


    You'll then need to resize the file system for the array, from the cli mdadm --grow /dev/md* (where * is your raid reference) --size=max

    hello
    i've done it using the gui of omv adding 2 drives (all 7 drives are excatly the same and the 3 i wantto add are brand new)


    Version : 1.2

    Creation Time : Mon Nov 9 22:15:42 2020

    Raid Level : raid5

    Array Size : 17581175808 (16766.72 GiB 18003.12 GB)

    Used Dev Size : 5860391936 (5588.91 GiB 6001.04 GB)

    Raid Devices : 4

    Total Devices : 6

    Persistence : Superblock is persistent


    Intent Bitmap : Internal


    Update Time : Mon Dec 7 17:05:27 2020

    State : clean

    Active Devices : 4

    Working Devices : 6

    Failed Devices : 0

    Spare Devices : 2


    Layout : left-symmetric

    Chunk Size : 512K


    Consistency Policy : bitmap


    Name : NAS:RAIDMAIN

    UUID : cf1e75d7:03d454e6:f2eb3f48:54436b07

    Events : 34222


    Number Major Minor RaidDevice State

    0 8 0 0 active sync /dev/sda

    1 8 16 1 active sync /dev/sdb

    2 8 32 2 active sync /dev/sdc

    4 8 48 3 active sync /dev/sdd


    5 8 64 - spare /dev/sde

    6 8 80 - spare /dev/sdf

    my last disk is still available if i try do expand it (but as i see it was adding the first 2 as spare i wait to have more information)
    BTW i'm a newbie !

  • Is there a way to do IT without loosing data ?

    There's no guarantee, but by that I would assume you don't have a back up in place. The reason I suggest to move to Raid 6 this would allow for 2 drive failures, you are intending to use 6 disks in that Raid 5. Even if you use the 7th drive as a spare mdadm does not add it to an array automatically should one of the drives fail.


    One way to do it would to add one of those drives to the existing array, so you would have 5 drives in the Raid 5 , then add the final drive converting to Raid 6 at the same time.


    To check how this would affect usable space try this raid calculator

    Raid is not a backup! Would you go skydiving without a parachute?

  • There's no guarantee, but by that I would assume you don't have a back up in place. The reason I suggest to move to Raid 6 this would allow for 2 drive failures, you are intending to use 6 disks in that Raid 5. Even if you use the 7th drive as a spare mdadm does not add it to an array automatically should one of the drives fail.


    One way to do it would to add one of those drives to the existing array, so you would have 5 drives in the Raid 5 , then add the final drive converting to Raid 6 at the same time.


    To check how this would affect usable space try this raid calculator

    thank you for this information,
    i don't know how to do it

    :)

  • What use the raid calculator


    BTW how did you add those 2 drives to the array

    i Use the OMV GUI
    a friend told me that maybe there's be a bug and when expanding array
    the OMV GUI don't send the GROW instruction but Only the ADD instruction ...
    he just help me to fix it
    using this command line : "mdadm --grow /dev/md127 --level=5 --raid-devices=6"
    and now the array is rebuilding

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