Benchmark-Request for ZFS 0.8 allocation classes


Distinguished Member
Feb 21, 2015
Saarland, Germany
Hi all,

has anyone already tried out the new allocation classes with spinners and SSD for e.g. metadata and can give benchmark results? What about the Proxmox Staff, have you tried it yet? The interest may be huge if you consider that we saw 10+ threads this year alone with "slow ZFS"-related topics on the forums.
Unfortunately, I haven't enough hardware lying around at the moment to give it a proper trial, but maybe someone can jump in.

no hard numbers (yet :)), but it should give a nice speed boost for things like:
- file servers
- containers
when you have lots and small files, or work loads where you create and delete files very often (for all of those things, you have lots of metadata operations).

keep in mind that you need two or three SSDs to not lose redundancy compared to the rest of the pool (unless you are running without redundancy there as well ;)), since special devices actually store data that is not stored elsewhere!
In the mean time, I build my first server with two enterprise SSDs for allocation classes and the OS itself and two vdevs consisting of 3 drives in raidz1 and it is noticeable faster than before, but I did not do a benchmark. Allocation classes are really great. You can create datasets and force them to the fast storage so that you will e.g. boot your OS from the SSD while all beeing part of only one pool. All metadata actions like listing of filesystems and snapshots is almost instantaneous.
  • Like
Reactions: aaron and fabian


The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get yours easily in our online shop.

Buy now!