ZFS Pool Size

  • I'm using (8) 8TB HDD's for my zfs pool. OMV picks up these drives as 7.28TB each in capacity. If I use the Raid-Z2 configuration, shouldn't that yield me 7.28*6=43.68TB? OMV is only showing 39.9 which is a loss of over 3TB.

    Case: U-NAS NSC-810
    Motherboard: ASRock - C236 WSI Mini ITX
    CPU: Core i7-6700
    Memory: 32GB Crucial DDR4-2133

  • Thanks for the reply.


    And ZFS wants us to maintain 20% free space? That's gonna be tough :D

    Case: U-NAS NSC-810
    Motherboard: ASRock - C236 WSI Mini ITX
    CPU: Core i7-6700
    Memory: 32GB Crucial DDR4-2133

  • Yeah, and from the looks of that slick looking case you have:I'll take it you're not inclined to adding a sas card, and using tin snips to run the cables out the side to an expansion chassis, right? :)


    I looked up your case. That's a nice box for a NAS.
    ______________________________________________________


    BTW, after posting, I went looking for file system overhead figures. I didn't find anything for ZFS which seemed odd, but I did find this. It's out of date but the figures are interesting.

    Interesting find. And nah, no sas cards :P Besides, I need to stop buying so many HDD's, my wife is going to kill me if I keep it up :P

    Case: U-NAS NSC-810
    Motherboard: ASRock - C236 WSI Mini ITX
    CPU: Core i7-6700
    Memory: 32GB Crucial DDR4-2133

  • Hi !


    I have 7x2To HDD (1,82To real) in a ZFS RAIDZ2 pool. This gives me about 8,2To off free space.


    That doc should help you a lot. You can see the parity cost depending on the number of disks vs RAIDZ you can choose, and you can then set the best block size.


    https://docs.google.com/spread…edit?pli=1#gid=2126998674


    For me, the best is 15 block/sector (40% lost), but I choose 128 block/sector (41% lost) as it suits me better.


    I have made a try with 4096/sector, and each file cost me x2 the real size ! So it is important to choose the right block size.
    Anyway, every change is taken for the new created file, so if you change the block/sector size, do it at the beginning or you'll have to cut/paste all your files to another drive to your pool.


    Just my 2 cents from my recent runs with ZFS...

    Lian Li PC-V354 (with Be Quiet! Silent Wings 3 fans)
    ASRock Rack x470D4U | AMD Ryzen 5 3600 | Crucial 16GB DDR4 2666MHz ECC | Intel x550T2 10Gb NIC

    1 x ADATA 8200 Pro 256MB NVMe for System/Caches/Logs/Downloads
    5 x Western Digital 10To HDD in RAID 6 for Datas
    1 x Western Digital 2To HDD for Backups

    Powered by OMV v5.6.26 & Linux kernel 5.10.x

    4 Mal editiert, zuletzt von sbocquet ()

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