Snapraid parity disks

  • Hi all


    Tried to do a bit of research, but couldn't find a solid answer to this question:


    I have:
    2x WD Red 4TB,
    2x spare HDD 2TB.


    I know that the parity disk should be the largest or equal largest disk in the array. However I'd prefer to keep the data on the new WD Reds I've just bought.


    Can I use the WD Reds for data disks, but use both regular HDDs as parity disks? As the two combined (4TB) is equal to the largest data disk size.


    Thanks

  • There is a solution for you that uses your two 2TB disks for parity. It is called "split parity." However, I don't think the OMV SnapRAID plugin can be used to configure it. You will have to do it by hand and I can't find the feature documented in the SnapRAID docs.

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


    OMV AMD64 5.x on ASRock Rack C2550D4I C0 Stepping - 16GB ECC - Silverstone DS380 + Silverstone DS380 DAS Box.

  • Hi all,


    First of all, I am solid with raspberry pi, pihole, & Debian Linux. I'm in the process of a new NAS build using the new Helios64 (5.9.11-rockchip64) + latest OMV5.5.17-3 Usul).


    I've got OMV main install working fine,, and I'm planning on configurating SnapRaid + Mergerfs Union file system when all disks mounted.


    I have set up (installed & mounted) 2 x 8TB hdd WD Red Plus' (CMR) to be data disks.

    I'm looking to set up another 8TB WD Red (SMR) as my one parity hdd.


    I read somewhere that if you have same size disks as the parity disk you should partition the data disks "slightly" smaller. Should I do this or am I being overly cautious (I'm an mechanical engineer and we're trained to be this way!)

  • I've never run into a problem not partitioning slightly smaller data disks. And my array is currently 10 disks of various sizes from 3TB to 12 TB with more than five years on the array.


    What you could do if you are really worried about this is format the data disks normally ( with the standard 5% reserved space) and for the parity disk reduce the reserve to zero. You can use the tune2fs program to check or set the reserve amount.


    PS


    I'm an ME too, retired though.

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


    OMV AMD64 5.x on ASRock Rack C2550D4I C0 Stepping - 16GB ECC - Silverstone DS380 + Silverstone DS380 DAS Box.

  • Thanks......good and easier thought on reducing the reserved space for the parity disk. Will use tune2fs to accomplish this.8)

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