ZFS on existing iSCSI Storage

[proxtux]

We have 2 Proxmox HA CLusters. One with iSCSI Storage using multipath and one using multipath on an Intel Modular Server (2 Storage Controllers).
At the moment we only use LVM for Disks.

This works good is fast and solid. But with raw Disks we can not make Snapshots.

So i think about using ZFS via iSCSI.
Is it possible to mix ZFS over iSCSI so i can use RAW LVM Disks and ZFS Volumes?

And is this a good idea to use on a productive System?

 

[wolfgang]

You can install in your ZFS vol what you want! I know no reasons why it should not used this way

 

[m.ardito]

I am learning zfs and would like to know better how to use it for the same purpose: storing raw disks on zfs to be able to take snapshots (like qcow2 ones?)

the zfs_over_iscsi wiki page seems to suggest that you can use proxmoxm zfs_over_iscsi storage plugin if you have one of the supported zfs backends: comstar, iet, istgt. and the pve gui seems to suggest that also.

now user proxtux asked for something different, afaik: use a regular iscsi proxmox target as "base" for zfs vols...
wolfgang states "sure!", but I am wondering if this is taking for granted that proxtux has one of those backends...

I thought, but I don't know if it's possible, to
- mount maybe 2, 3 luns from my iscsi nas with the regular iscsi plugin (the same used as "base" for lvm)
- configure local zfs to use those "iscsi mounted disks" to create a pool, and create a zvol for a vm on it.

is this possible and how, precisely should one proceed? is it possible from the gui? or only from CLI (and how)?

Thanks,
Marco

 

[wolfgang]

Yes it would be possible to use zfs on to of iscsi target. I mean, I know it is possible on BSD, but I never tried it on Linux.
But IMHO it makes no sense. You get only all disadvantages from both systems.
You can not do this from Gui. This is a manual configuration task.

 

[m.ardito]

You get only all disadvantages from both systems.

I'm sure you are right, but in order to fully understand, could you please elaborate a bit more on why you think so?

Thanks, Marco

 

[wolfgang]

Ok iSCSI has very mutch problems on desing on latencys.
So if you have a raid what generally is very senseble to this kind of problems.
Therefor you will resilver the hole time to keep the data in sync, what cost much performance.