Best practice on using a degraded pool

[Burlumpu Bumpu]

Hello all

I've been looking for some information about usage of a degraded pool. Obviousely, it should be repaired immediately, and there's a lot of information about this on this forum. What I could not find in the forum or the documentation:

- Is it safe to use a degraded pool while (scrubbing /) resilver? What is best practice?

In my case I have a RAIDZ2 with 2 vdefs (16x 4TB SAS drives in total). I am currently paying the price for buying older enterprise HDD's, one left this world without even saying goodbye. I am resilvering, but it takes a looong time. Still I want to provide access to my Plex Server, which sources the data off a freenas dataset. Is this recommended/allowed?

Thanks and kind regards

Alex

 

[PhiloEpisteme]

In my case I have a RAIDZ2 with 2 vdefs (16x 4TB SAS drives in total). I am currently paying the price for buying older enterprise HDD's, one left this world without even saying goodbye. I am resilvering, but it takes a looong time. Still I want to provide access to my

It is expected that in MANY use cases one will be using a pool while resilvering. If you have quality backups of your data you should have no fear about using it while resilvering or performing a scrub. If you have no backups and you're on the limit of the redundancy of your pool I'd suggest you use it as little as possible until you resilver enough disks to get at least 1 disk worth of parity. For example, if you lost 2 drives in your RAIDZ2 vdev you may consider reducing usage but if you only lost 1 you should be fine using it while you resilver.

 

[Jessep]

Being able to use the pool during resilvers was one of the design goal of ZFS (or any redundant FS). Reduced performance not loss of access, ideally your end users don't even notice the difference.

 

[Burlumpu Bumpu]

Ok, thanks! Sadly I do NOT have a backup of this data. I plan on expanding the rack but it's not possible right now...

 

[PhiloEpisteme]

Ok, thanks! Sadly I do NOT have a backup of this data. I plan on expanding the rack but it's not possible right now...

Some guidance on backups. The 3-2-1 rule has some merit and is worth considering. Basically you should have 3 copies of your data stored on at least 2 different types of media with at least 1 copy of your data off-site. This will protect you in the event of fire, flood, system-wide catastrophe etc. Worth keeping in mind as you consider backup strategies.