Four Disks - What's Optimal?

[Draznar]

I had a NAS box with 2 disks, in a mirror mode. Wanting to expand my storage capacity I have purchased two additional disks, so I now have 4 x 2TB disks.

I am rebuilding the NAS box from scratch and am trying to decide the best way to organize the disks. My first thought was just to do a 4 disk Raidz all in one vDev. Now I am wondering if it would be better to create two vDevs of 2 disks in a mirror, both in the same ZPool. What is the process for determining the ideal configuration? In the Raidz, I think I am ok with only able to handle 1 disk failing (3 storage + 1 parity)

Thoughts? Thank you for any insight.

[b0ssman]

it depends on how important your data is.

in the raidz1 if one dies and during the rebuild another one dies you lost all your data.
same with the dual mirror, if the wrong disk dies.

you could go for a raidz2 setup. then 2 disks could die and your data is still safe.

[apollo567]

RaidZ1 then with 4 disks
If u want to have a greater reliability/higher fault tolerance go for RaidZ2 with 6 Disks. Many Mainboards support up to 6 disks, beyond its an other step effortwise...

[ku-gew]

The same question has been posted so many times. Have you checked the forum?

RAID10 gives best performances, fastest rebuild and therefore very low risk (especially if you use one old and one new disk per pair, assumed they are all 4 the same size)
RAIDz1 gives the most space, worst safety
RAIDz2 gives in practice total security, but worst performances (I am talking about useful performances: small files, since big files are less influenced).