Proxmox backup server best practice

[Sammy01]

Hello everyone,

We have just started testing PBS Server and would like to have recommendations for the best practice possible.

We have 20x disks with 16Tb of capacity each. We have few more slots empty for more disks. So adding hot spares won't be a problem.
Should we build a hardware or software RAID z and in which scenario?
Should we use extra SSDs for the metadata? How many and with how much capacity should be enough?

We want the maximun capacity possible with good performance (shouldn't have to super fast) for backups and in case of a disk failure (RAID rebuild).

 

[Dunuin]

I would recommend to use ZFS with HBAs as a striped mirror (raid1) so you can use SSDs for metadata so GC won't take an eternity to finish. SSDs should be reasonable mirrored (three-disk mirror) and have around 0.4% of the HDDs total capacity.

Don't use a raidz1/2/3 as PBS needs high IOPS performance and IOPS performance will only scale with the number of striped vdevs, not with the number of disks. So 20 disks in a raidz wouldn't be faster than a single HDD.
And resilvering would also take forever.

So with a striped mirror around 40% of the HDDs raw capacity would be usable for backups in case of 2 disks per mirror and 26,6% of raw capacity in case of 3-disk mirrors.

And recommended would be a SSD-only storage. With that a striped raidz2 also becomes more reasonable as the IOPS performance is magnitudes higher. A raidz consisting of good SSDs would still be performing better than a striped mirror of hundreds of HDDs.