zfs nesting reduce write amplification

[VinnyG]

hello,


I'm running an opnsense firewall guest and filesystem is ZFS, this the only "production" instance right now i have disabled some ZFS features on the guest already just wanted a confirmation that this is harmless:
checksum
compression
encryption
sync
xattr=sa

also should i disable the primary/secondary caches on zfs settings?

what about setting write-back cache on pve

which other options one can tune to prevent double writing on a nested zfs?


Thanks a lot.

 

[IsThisThingOn]

which other options one can tune to prevent double writing on a nested zfs?

Why would you even use nested ZFS? Isn't that just asking for trouble?

 

[Kingneutron]

If the guest is running zfs, you'd be well advised to move the vdisk to lvm-thin. Two levels of COW is ... not great

 

[VinnyG]

Why would you even use nested ZFS? Isn't that just asking for trouble?

the OS only has ZFS and UFS options, i read that ufs is too old etc

 

[VinnyG]

If the guest is running zfs, you'd be well advised to move the vdisk to lvm-thin. Two levels of COW is ... not great

yeah so that would be the "sync" option which I disabled right? i see that some people run ZFS in async mode and in that case it's not losing anything as the host sync is enabled

what else i could be looking for?

 

[IsThisThingOn]

I would rather switch to none ZFS guests.