Install Proxmox on a 2 drive ZFS mirror if one is a NVMe SSD and the other is a SATA SSD or stick to 1 NVMe SSD and use the SATA SSD as simple BU?

[dakazze]

I am currently building my new home server around a miniPC (Xeon+ECC RAM) so my possibilities are limited. The PC has 2x m.2 slots and 1 SATA slot but I need one of the M.2 slots for a 6x SATA controller for my NAS Storage.
The install SSD will host Proxmox, my VMs and a bit of storage for the VMs, ISOs, etc.
So as I see it I can either set up a ZFS Mirror between a NVME SSD and a SATA SSD or skip the mirror and use the SATA SSD for a simple hypervisor and VM backup. (A few hours of downtime to restore a BU would be OK for my needs)
Oh and if I go the ZFS mirror route, do I need to do any partitioning for the above mentioned use?

What would you pros suggest? As a complete noob I would really appreciate your help!

 

[guruevi]

I would make sure your backup is not IN the same computer, ideally not in the same physical or geographical area.

Will your SATA disk be fast enough to run your desired workload is the question? If so, then I don’t see a problem, if not then perhaps use the SATA to boot, the NVMe for your VMs and then an external backup of both.

 

[dakazze]

I would make sure your backup is not IN the same computer, ideally not in the same physical or geographical area.

Will your SATA disk be fast enough to run your desired workload is the question? If so, then I don’t see a problem, if not then perhaps use the SATA to boot, the NVMe for your VMs and then an external backup of both.

.... oh you got me there - a BU on this machine does not make much sense since I am setting my old machine up as a BU-Server on the other end of the property!

For most of the stuff I do it does not really matter if it is run from a SSD or a HDD so the difference between SATA and NVMe SSD wont matter at all.

If I didnt get this wrong on a setup like this (ZFS NVMe+SATA SSD) I should get even more read speed but less write speed, which would make most processes faster, or am I mistaken?

I would also really appreciate if someone could chime in about my partitioning question.

Oh and if I go the ZFS mirror route, do I need to do any partitioning for the above mentioned use? (Proxmox + VM + bit of storage)

 

[guruevi]

It could POTENTIALLY make it faster. In worst case scenario (which is what typically people size their systems for) it's as fast as the slowest drive both in read and writes, in best case, your system returns as fast as the fastest drive from a read and for synced writes it should be as fast as the slowest drive, but certain types of writes in certain conditions may be faster.

As far as partitioning, it's possible to do, provided you are aware of the limitations, basically you share the bandwidth and the 'extra data' is not in your mirror, if you are okay with that, professional NVMe drives do have the concept of namespaces as well, so that way you don't have to mess around with any partitioning issues.

As with all these non-recommended setups, it is possible to do, just don't be surprised when it goes horribly wrong and eats your data, in most cases data safety and availability trumps the 'cost' of an extra drive/controller/...

 

[leesteken]

I have combined HDDs and a NVMe in a ZFS mirror and (small, random) reads very much improved. I ran NVMe and SSD in mirrors before and it worked fine. Recent versions of (Linux) ZFS got much better at reading from the fastest drive (in a mirror).