ZFS or normal Raid

[scottf007]

Hi All, 

I am on my Helios64 (already have a Helios4). 

I am running 2 x 8TB, 1x 256 M2, OMV5 debian etc.

 

I have ZFS running (from the wiki instructions) in a basic mirror format, and if I add a few drives I think it would still be a mirror, however I have the following question. It seems far more complicated than MDADM, and potentially more unstable (not in terms of the underlying technology, but in terms of changing these kernals etc every week). 

Do you think for an average home user that this is really worth it or will constantly need work? To change it would mean starting again, but I do not want to change the setup every month and would intend to keep it stable for media, and backing up some stuff for the next few years. Or if it is working it should be fine for the long term?

 

Cheers
Scott

[hartraft]

Regarding stability of the helios64 and the support of ZFS on ARM, why wouldn't a more preferred setup be normal RAID, mergerfs/SnapRaid or MooseFS as some have run in other setups? 

 

I'm asking from a naive point of view, no disrespect for ZFS. I already heard of its prowess in x86 Solaris/FreeBSD/Linux. Just looking for the most stable environment for "the current situation" 

[ShadowDance]

@scottf007 I think it would be hard for anyone here to really answer if it's worth it or not [for you]. In your situation, I'd try to evaluate whether or not you need the features that ZFS give you. For instance, ZFS snapshots is something you never really need, until you do. When you find that you've deleted some data a month ago and can still recover it from a snapshot, it's a great comfort. If that's something you value, btrfs could be an alternative and is already built into the kernel. If all you need is data integrity, you could consider dm-integrity+mdraid and file system of choice on top (EXT4, XFS, etc.). Skipping "raid" all-together would also be possible, LVM allows for great flexibility with disks.

 

If you're worried about the amount of work you need to put in with ZFS, you can freeze the updates when you are satisfied with the stability of the system. Just hit `sudo apt-mark hold linux-image-current-rockchip64 linux-dtb-current-rockchip64` which prevents kernel/boot instruction updates and you should not have ZFS break on you any time soon. Conversely, `unhold` once you're ready to deal with the future.

 

For me personally, ZFS is totally worth it. I have it on two server/NAS at home. I use ZFS native encryption on one, and LUKS+ZFS on the Helios64 (due to CPU capabilities). I also use a tool named zrepl for automatically creating, pruning and replicating snapshots. So for instance, my most important datasets are backed up from my one machine to the Helios64 in raw mode, this means the data is safe, but not readable by the Helios64 without loading the encryption keys. I also run Armbian on the Helios64 straight off of ZFS (root on ZFS), this gives me the ability to easily roll-back the system if, say, an update broke it.

 

@hartraft depends on your requirements/feature wishlist. RAID (mdraid), for instance, cannot guarantee data consistency (unless stacked with dm-integrity). What this means is that once data is written to the disk, it can still become corrupted and RAID can't catch it. ZFS guards against this via checksums on all data, i.e. once it's on disk, it's guarantee-ably either not corrupted or that corruption will be detected and likely repairable from one of the redundant disks. ZFS also has support for snapshots, meaning you can easily recover deleted files from snapshots, etc. RAID does not support anything like this. Looking at mergerfs, it seems to lack these features as well, and it runs in user-space (via FUSE), so not as integrated. SnapRaid is a backup program so not really comparable and MooseFS I know nothing about, but looks enterprise-y.

 

The closest match-up for ZFS in terms of features is probably btrfs (in kernel) or bcachefs (have never used this).