PVE 7 on ZFS: put root FS on two HDD or on two SSD?

alexc

Active Member
Apr 13, 2015
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I have a server, which equipped with 2 x 2Tb HDD and 2 х 512 Gb SSD disks. I'd like to install PVE 7.0.2 on it, and plan to create mirrors out of these disks.

So, I really doubt, if I should install PVE (OS) itself on SSD ZFS mirror or on HDD ZFS mirror? Both approaches are appears to have its pros and cons. Sadly, I have no h/w RAID card so the only option is ZFS as the only one that's supported. Personally I'd prefer use MD raid but I also like ZFS periodic scrubs.

I plan to use rest of mirror to put VMs.

Please advice!
 

Dunuin

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Jun 30, 2020
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You can install a normal Debian 11 with mdadm raid and then install PVE ontop of Debian if you really want mdadm and no ZFS. But keep in mind that mdadm isn't officially supported and isn'T recommended because it is missing all the data integety features of ZFS.
PVE will run fine with just 16GB of storage. And you can use the same storage for PVE+VMs so its really up to you if you want to install PVE on a HDD or SSD mirror.
 
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alexc

Active Member
Apr 13, 2015
123
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38
You can install a normal Debian 11 with mdadm raid and then install PVE ontop of Debian if you really want mdadm and no ZFS. But keep in mind that mdadm isn't officially supported and isn'T recommended because it is missing all the data integety features of ZFS.
PVE will run fine with just 16GB of storage. And you can use the same storage for PVE+VMs so its really up to you if you want to install PVE on a HDD or SSD mirror.
Glad to get your answer, thank you! But mind if I please ask you to answer the question in title: which mirror should I prefer to OS install, SSD or HDD?
 

Dunuin

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Jun 30, 2020
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which mirror should I prefer to OS install, SSD or HDD?
That really doesn't matter. PVE doesn't need great performance and is only writing around 30GB per day. So both will be fine.
I would install PVE to the mirror that you least want to replace/extend in the future if you plan to store VMs on both mirrors. So you can destroy and recreate the other mirror without needing to reinstall PVE.
What do you plan to use the HDDs mirror and SSD mirror for?
 
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chrcoluk

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Oct 7, 2018
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Proxmox will write a load of data if you like to keep a idle connection in the web UI, every 2 seconds or so a web access is logged in /var/log/pveproxy (and also nginx if you have it as a frontend), I found this was causing 10s of gigs of writes a day to my rpool ssd's. So this might be considered if you have a concern for nand endurance,
 

Tahsin

Active Member
Mar 24, 2018
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Proxmox will write a load of data if you like to keep a idle connection in the web UI, every 2 seconds or so a web access is logged in /var/log/pveproxy (and also nginx if you have it as a frontend), I found this was causing 10s of gigs of writes a day to my rpool ssd's. So this might be considered if you have a concern for nand endurance,
That might explain why my SSDs going through its TBW rating like no other.
 

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