zfs Pool in 9.1

[Drk]

Setup 2 raid cards with 16 drvies.

Would it be better to build one big raidz3 or 3 raidz. But i am not sure why it is not optimal. Than would it be better to use one of the volumes as stripe and not raidz.

 

[paleoN]

Would it be better to build one big raidz3 or 3 raidz.

Neither. I would go with 2 x 8 x disk raidz2 vdevs.

But i am not sure why it is not optimal.

Simple, the last vdev is configured with an additional drive vs. the other two. Change it to a spare and it will be 'optimal'. Like I said though, raidz2.

 

[Drk]

Simple, the last vdev is configured with an additional drive vs. the other two. Change it to a spare and it will be 'optimal'. Like I said though, raidz2.

I understand that but really is there a reason why? Why 2 and not 3 vdev?

 

[paleoN]

I understand that but really is there a reason why?

Because all the vdevs need to have the same number of disks or else they will eventually be unbalanced. Not to mention 6 x disk raidz1 isn't optimal anyway.

Why 2 and not 3 vdev?

raidz2

Code:

8 + 8 = 16

;)

 

[Drk]

Because all the vdevs need to have the same number of disks or else they will eventually be unbalanced. Not to mention 6 x disk raidz1 isn't optimal anyway.

Ok, makes since but funny thing is that raidz2 is not optimal pre freenas. When i do 3*6 it does say, going to go with 2*8

 

[paleoN]

Ok, makes since but funny thing is that raidz2 is not optimal pre freenas. When i do 3*6 it does say, going to go with 2*8

Yes, an 8 x disk raidz2 isn't optimal. That would be 4, 6 or 10. I assume you want to use all your disks and wouldn't want to use 4 x 4 x disk raidz2 vdevs. You could also go with two pools with 2 x 6 x raidz2 vdevs and 4 x disk raidz2 pools. I wouldn't worry too much about it though.