ZFS: ZFS Pool Sizing easy calculation

ZFS Reserves 1/64th of pool capacity for saveguard to protect COW.

So if you create a pool of several disks you’ll lose capacity containing the kind of raidz.

ZPool sizing: <disks (-parity of Raidz-level)> * <GB Capacity> / 1.016 = GB/TiB Usable Space !

 

4 Disks of 100 GB = 400 GB.

400 / 1.016 = ~390

= ~ 390 GB Usable Capacit

Exampels:

– RAIDZ1 Space is drive’s total capacity -1 drive.

– RAIDZ2 Space is drive’s total capacity -2 drive

– Dyncmic STRIPE of 4* 100GB = 400 / 1.016 = ~390GB

– Dyncmic STRIPE of 8* 2TiB = 16 TiB / 1.016 = ~15,7 TiB

– RAIDZ1 of 4* 100GB = 300 / 1.016 = ~295GB

– RAIDZ1 of 8* 2000GB = 14000 / 1.016 = ~13,7TiB

– RAIDZ2 of 4* 100GB = 200 / 1.016 = ~195GB

– RAIDZ2 of 8* 2000GB = 12000 / 1.016 = ~11,8TiB