(Snapraid) Migrating 5 drives to 4 drives - Full sync gives "you must have at least 3 content files"

  • Had a previous snapraid array with 5 drives. 3 were data + content and 2 were parity. I've since migrated to 4 larger drives. 2 being data + content and 2 for parity. I've deleted all snapraid.parity, snapraid.2-parity as well as all snpraid.content files.


    When I try to do a full sync with the new drives, I get the above error about needing 3 content files. /etc/snapraid.conf lists the new drive configuration(2 data/content + 2 parity) and no 3rd content file. What gives? Is OMV hanging onto the previous snapraid config somewhere? Anyone run into this?

  • baggar11

    Changed the title of the thread from “Migrating 5 drives to 4 drives - Full sync gives "you must have at least 3 content files"” to “(Snapraid) Migrating 5 drives to 4 drives - Full sync gives "you must have at least 3 content files"”.
  • Just add content files to both parity drives, giving you four.

    --
    Google is your friend and Bob's your uncle!


    OMV AMD64 7.x on headless Chenbro NR12000 1U 1x 8m Quad Core E3-1220 3.1GHz 32GB ECC RAM.

  • It's looking more and more like I'll have to add content files to the parity disks as you suggest.


    Just seems strange that I blew away all previous snapraid config, including the content and parity files, and only have the new /etc/snapraid.conf file that defines the new 4 drive array. Why and how is snapraid still pulling configuration from the previous 5 drive array. Thanks for replying.

  • Depends on how you removed those things. Did you use the plugin to do this? If not there can be remnants left over in OMV's database.

    --
    Google is your friend and Bob's your uncle!


    OMV AMD64 7.x on headless Chenbro NR12000 1U 1x 8m Quad Core E3-1220 3.1GHz 32GB ECC RAM.

  • That sounds like what may be happening then. Although I searched the /etc/openmediavault/config.xml file for the snapraid config. It looked to mirror the 4 drive config. Assuming that config.xml file is the OMV dB.


    As far as removing the old array, I used the plugin for some portions of the removal process. Then manually deleted the content and parity files on the FS via CLI before using the plugin to create the new configuration.

  • Well, I guess it may be that snapraid requires a minimum of 3 content files. Didn't know that and wasn't able to find it in the snapraid docs. I had a response over at the snapraid subreddit and was told so. So, I'll trust the advice, add a content file to one of the parity disks and be done with it. Thanks again for your help.

  • I have always placed a content file on every disk in the array. Maybe why I have never seen this warning.

    --
    Google is your friend and Bob's your uncle!


    OMV AMD64 7.x on headless Chenbro NR12000 1U 1x 8m Quad Core E3-1220 3.1GHz 32GB ECC RAM.

  • I thought I had read about it not being ideal to put content files on parity disks because of the potential for both to eat up space. Especially with large amounts of small files. Oh well, my array is off on a full sync now. 24 hours remaining...

  • That's a valid concern, but in many years of doing this it never became a problem. My content file is a 4.671GB and my mergerfs pool drives have 100GB reserves.


    I suggest not having any filesystem reserved blocks on your parity disks. And if you have any disks 16TB or larger in your array, you should format your parity disks ZFS.

    --
    Google is your friend and Bob's your uncle!


    OMV AMD64 7.x on headless Chenbro NR12000 1U 1x 8m Quad Core E3-1220 3.1GHz 32GB ECC RAM.

  • Well, I guess it may be that snapraid requires a minimum of 3 content files. Didn't know that and wasn't able to find it in the snapraid docs.

    From the manual:

    7.4 content FILE

    Snip.....

    You have to store at least one copy for each parity disk used plus one. Using some more doesn't hurt.

    --
    Google is your friend and Bob's your uncle!


    OMV AMD64 7.x on headless Chenbro NR12000 1U 1x 8m Quad Core E3-1220 3.1GHz 32GB ECC RAM.

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