18TB 4 HDD trying to learn the best config for them

TrueNAS General
1

Hello all,

         Four 18TB HDD what is the recommended raidz for them, they will be used as a file server...

Jeff
2

Long answer; depends on your personal risk tollerance &/or performance needs.

Short answer; go raidz2.

3 Likes
3

So I saw where it was recommended z2 but was also wondering if 3 would work or is it highly suggested that it be 4?

4

“3” what? “4” what?
Raidz3 needs at least five drives.
Raidz2 needs at least four drives.

5

He probably meant 3 disks in raidz2 or 4 disks in raidz2…

6

So with just three disks a raidz1 is possible, but if one disk fails, you are uncomfortably close to total data loss until you get a replacement disk and the resilver, which stresses the remaining drives and will take quite long (maybe serveral days even?) has finished.

7

Yes 3 disks vice 4, since this is used as a file server for users to place documents/apps/patching/ and such, speed is not that important, more value is placed on recoverable and time to restore…

8

So it looks like 4 is the recommended path

1 Like
9

Yes, a pair of mirrors is very safe, you can lose two drives and still keep running. Also less stress if one drive is lost and needs to be replaced.

10

Well you can loose one drive in each vdev, if you loose both drives in one vdev you’re in trouble…

11

Yeah that was assumed. With two mirrors. You’d have two separate arrays and could lose one drive from each.

I can be more pedantic if necessary, but I prefer to give the reader some credit. :wink: