RaptorBeaver Posted June 2 Share Posted June 2 Hello guys, New to unraid and i love it ! I read a lot of documentation about ZFS... I created a ZFS Pool with 2 slot nvme drives in raid0 and i have some questions... - I add 2 disk (same than 2 first ones) by switching the number of slot from 2 to 4... I had no problem... I thought we cannot expand zfs pools so i don't understand why does it work...? - I read that if we don't have multiple vdevs with ZFS we don't cumulate speed... The max speed is the speed of the fastest disk. Is that true with unraid ? - I see no information regarding vdevs with ZFS Pool in unraid... How does it works ? Regarding my previous question if i want to get max speed of my pool i need to be able to configure my vdevs... For this pool it's not really important because it is a small pool just for performance without any parity but i plan to put a lot of ssd together in another pool with parity and i wanted to know before that what will happen regarding expandability, performance, vdevs and co... Sorry to bother you with theses simple questions but the unraid manual part regarding ZFS is pretty small... Thanks a lot Quote Link to comment
JorgeB Posted June 2 Share Posted June 2 55 minutes ago, RaptorBeaver said: I thought we cannot expand zfs pools so i don't understand why does it work...? Depends on the pool, mirrors can only be expanded by adding another mirror, raidz only with a new vdev of the same type and with, striped/raid0 pools can always be expanded, even by adding a single device, since they are always part of the same vdev. 57 minutes ago, RaptorBeaver said: I read that if we don't have multiple vdevs with ZFS we don't cumulate speed Striped vdevs will still use all devices, despite being all from the same vdev, and raidz with a single vdev is still faster than a single disk for sequential read/write speed, but not for iops, to increase that you would need to stripe a new vdev Quote Link to comment
RaptorBeaver Posted June 2 Author Share Posted June 2 Thanks a lot for your reply, how can I see vdevs in unraid ? Because for now i can add pool see differents pools, disks etc, but i cannot find the vdev identification/definition... Quote Link to comment
JorgeB Posted June 2 Share Posted June 2 On main click on the pool and scroll down to the zpool status section. Quote Link to comment
RaptorBeaver Posted June 2 Author Share Posted June 2 Thanks, So basically with this output i can considere i only have 1 vdev ? pool: mypool state: ONLINE config: NAME STATE READ WRITE CKSUM mypool ONLINE 0 0 0 /dev/nvme2n1p1 ONLINE 0 0 0 /dev/nvme3n1p1 ONLINE 0 0 0 /dev/nvme0n1p1 ONLINE 0 0 0 /dev/nvme1n1p1 ONLINE 0 0 0 errors: No known data errors Quote Link to comment
JorgeB Posted June 2 Share Posted June 2 1 hour ago, RaptorBeaver said: So basically with this output i can considere i only have 1 vdev ? Yes, and as mentioned raid0/stripe can only use one vdev, if you think about it, you cannot stripe a vdev to already striped devices. Quote Link to comment
RaptorBeaver Posted June 2 Author Share Posted June 2 (edited) Yes understood.... What do you recommand in terms of vdev design if i put 15x SSD disk together as a pool ? I'm hesitating between having 15x SSDs and 3 vdev so 3 parity disks and having 14x SSDs and 2x 7 disks vdev with 2 parity disks Edited June 2 by RaptorBeaver Quote Link to comment
Solution JorgeB Posted June 3 Solution Share Posted June 3 Assuming you want some redundancy I would created two raidz1 vdevs, if you can use 14 or 16 devices, if you really want 15 then three raidz1 vdevs, or maybe just a single raidz2 vdev with all 15, depending on what the pool is going to be used for. Quote Link to comment
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