Proxmox PVE on ZFS

[moose]

Hi folks,

so far I ran the current PVE release on my HP Proliant Microserver Gen10 (not +) X3421 on 2 HDDs configured as RAID1 managed by the boards onboard Marvell RAID controller. This works fine and relialbe for me over years now.

Although the systems overall performs good (for my needs, im just running 4-6 VMs) the bottlenack is the disc access of the VMs (currently implemented LVM volumes) which is sometimes a litte bit poor. Because I need more disc space anyway (and I already setup a FreeNAS server for backup only) I decided to switch PVE to ZFS for the VM's discs. I'll build a RAID-Z with three HDDs and will use one small SSD for booting and the hosts OS.

The thing why I'd kindly ask for your experiences is as follows:

Additionally I can add a PCIe Controller for 2 m.2 drives which I want to configure as RAID1. This device I'd like to use for ZFS's ZIL and L2ARC cache.

Does anybody run this configuration and is there noticeable improvemet in data access of the VMs discs?

Do you have any further tipps or hints related to this topic?

Many thanks in advance!

Greetinx,

moose

 

[Dunuin]

SLOG and L2ARC will most of the time not give you a big performance improvement.
SLOG only write caches sync writes and I guess most of your writes will be async where the SLOG won't be used at all.
And with a L2ARC as read cache you are sacrificing a bit of way faster RAM cache to get some more but slower SSD cache. So sometimes that might even end up slower and a L2ARC might slow you down.

If you think your HDDs are too slow in a HW raid1 it won't be much better with ZFS. Especially for IOPS performance which you need the most with HDDs a raidz1 won't be faster than a raid1 as IOPS performance won't scale with the number of disks. And ZFS got alot of overhead and write amplification, so a hardware raid is usually faster.
Better to move away from HDDs and run your guest on SSDs, if you think the HDD performance is a bit low, than buying new SSDs and HDDs to speed up your existing HDDs.

So I would either turn your HW raid1 into a HW raid10 to double the IOPS performance or switch completely to SSD for your VM storage.

 

[moose]

@Dunuin Many thanks for your reply and your suggestions!