ZFS Best Pratices

[halley80]

Hello,

I have a blade in my cluster with a 32TB pool (ZFS raidz1-0).
5x7.2Tb 7.2k HDD

Can the whole pool be used directly or is it better to "cut it out". (3x10TB ?)
"Don't create massive storage pools "just because you can." Even though ZFS can create 78-bit storage pool sizes."

I'm thinking in particular of the fragmentation of the free space in ZFS. (cf "zpool list" of my cluster )
I read in the different posts that some reached fragmentation values of more than 70%, what are the consequences?
Concerning the Ram used, is 1GB for 1TB of disk a reasonable value?

Thank you for your answers
Sincerely

 

[guletz]

Can the whole pool be used directly or is it better to "cut it out". (3x10TB ?)

Cut it. Anyway with this big hdds using a raidz1 is a big lottery. If one hdd will be broken, maybe you will have a replacement disk in the next business day. Then during the resilver procces of the pool who will take probably more then one day it is possible to face it a new broken disk (during the resilver all your hdd will be overloaded )

I would condider to use a raid10 (3x 10 TB + a spare disk). Also the performance will be better(3 x iops of one disk). The resilver will be also faster compared with raidz1.

 

[guletz]

Can the whole pool be used directly or is it better to "cut it out". (3x10TB ?)

Cut it. Anyway with this big hdds using a raidz1 is a big lottery. If one hdd will be broken, maybe you will have a replacement disk in the next business day. Then during the resilver procces of the pool who will take probably more then one day it is possible to face it a new broken disk (during the resilver all your hdd will be overloaded )

I would condider to use a raid10 (3x mirror of 2x 10 TB + a spare disk). Also the performance will be better(3 x iops of one disk). The resilver will be also faster compared with raidz1.