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> I prefer the raid5 approach I've been using actual raid5 (via adaptec raid card) for years and very recently had one of my trusty 5TB HGST drives fail (after
by canada_dry 6y ago
> I prefer the raid5 approach
I've been using actual raid5 (via adaptec raid card) for years and very recently had one of my trusty 5TB HGST drives fail (after 3+ yrs of uptime).
Fortunately the rebuild worked, but there are so many horror stories of raid5 rebuilds NOT working it has me contemplating going back to simple mirroring.
- PureParadigm 6y agoRAID is not a replacement for backups. In the case with Steam the top level comment mentioned, all files writable by the user were deleted (including mounted drives in /media). RAID might protect you against hardware failure, but you also have to consider software (bugs/hackers/ransomware).
- canada_dry 6y ago> RAID is not a replacement for backups. As an IT Exec (retired)... this was a lesson learned long ago. For my own/home systems I use rclone [i] (in conj w raid5) for the most critical files. [i] https://github.com/rclone/rclone https://github.com/rclone/rclone
- cure 6y agoWhoa. You were lucky. Very lucky. If you are going to use hardware raid, please do make sure you have a spare raid controller, same firmware, same model. If not, you will be SOL when your controller dies. RAID5 these days (with our very large disks) is basically asking for trouble - the odds of a second disk failing during the reconstruction are very high. But I guess you already know that!
- hondo77 6y agoI've had raid5 rebuilds work. Until the last one. One of the remaining drives failed during the rebuild.
- c22 6y agoI used to run with simple mirrored drives. One time the master drive experienced some corruption and wouldn't boot. In attempting to fix the issue I mixed up the identifiers of each drive and ended up hosing the mirror as well. Now I use a more sophisticated RAID10 setup and really appreciate the way failed and replaced drives automatically rebuild themselves without my dumb interaction.
- jankiehodgpodge 6y agoYou probably want to bump that toRAID 6 at least. Rebuild times on arrays that big can be long, especially if it takes a while to get a replacement drive. Plus most RAID controllers can protect against bit rot when in RAID 6 because it determine if bits get flipped. On RAID 5, you don't have that option.
- cyphar 6y agoMirrors are generally better because you get shorter resilver times and you don't stress all the disks in your pool when you resilver (which is why a lot of disk failures happen during RAID5 rebuilds -- the rest of the pool's disks are old). The downside is that it uses more disks for the same level of redundancy. I would also mention it's probably a good idea to use something like ZFS rather than a hardware RAID card. In general, free software RAID is better audited and you don't need specific hardware for the recovery process. But also, ZFS has proper checksumming, so you won't have to worry about all sorts of silent corruption (which RAID blissfully ignores -- most implementations will just recompute the parity in case of a mismatch, which is the wrong thing to do (1-1/n) of the time).
- canada_dry 6y ago> a good idea to use something like ZFS Was hoping to utilize ZFS in 20.04... but the whole SNAP issue has me sticking with my current version. Perhaps it's time to find a dummies guide to setting up ZFS on 18.04 LTS.
- lmm 6y agoHave you considered FreeBSD? ZFS support by default, and none of the junk that recent Linux distributions have been moving towards.
- NickNameNick 6y agoI had to rebuild a raidz+1 last year. Went OK, except the replacement disk turns out to be an SMR disk... The rebuild took almost 2 weeks.