ZFS ZFS vfs.zfs.spa_slop_shift

[Gherardo]

Hi,

I have 12 disks in a raidz2 system (2 vdevs) that I use mostly as NAS for storage (backups and few movies).
Given that the system is basically write once, read many, I'd like to be able to use most of the available space.

ZFS by default is reserving 1/32 of space for operations, and I wanted to reduce this amount
So I used vfs.zfs.spa_slop_shift command:

sysctl vfs.zfs.spa_slop_shift=6
vfs.zfs.spa_slop_shift: 5 -> 6

The command works zfs list shows more space available and everything seems ok.
Problem is that, when I reboot, vfs.zfs.spa_slop_shift is again 5.

sysctl -a | grep vfs.zfs.spa_slop_shift
vfs.zfs.spa_slop_shift: 5

I'm on FreeBSD 12.2-RELEASE r366954 GENERIC btw.
Am I doing something wrong? Is there a way to make the change permanent?

Thanks in advance,

Gherardo

 

[SirDice]

Am I doing something wrong?

The sysctl(8) command only changes running settings. They are not permanent.

Is there a way to make the change permanent?

Add it to sysctl.conf(5).

 

[Gherardo]

Thank you!