separate boot zfs and storage zfs


Well-Known Member
Apr 22, 2017
Hy all,

is there any performance win or other advantage with a separate zfs pool for boot and zfs pool for storage (vm, container).
Till now i always builded upon 1 zfs pool for boot and storage.

Kind regards and thanks for any advice
performance may or may not be meaningfully affected but its best practice to keep your boot device(s) and data device(s) separate in case the boot device fails/dies or you want to move the data to another os/hardware.
is there any performance win
... in most cases, the performances will be bad, because using 2 different zfs pools, will reduce the ARC cache usable for each pool(assumming that you will alocate the default, around 50% total RAM). The only case that I can imagine to be acceptable(for performance point of view + saftey) will be to have one zfs pool using 2xSSD(mirror), with ARC for metadata only and another zfs pool(with whatever ....).
Thanks, i suspected allready that more zfs pools would have consequences on the ARC cache.
Would a separate ssd for cache (l2) and log be beneficial then?
A single ssd with ext4 for booting proxmox only seems the alternative, but you sacrifice redundancy on the booting device then.
Not a perfect world...
Would a separate ssd for cache (l2) and log be beneficial then?

Maybe, but could be many variables in this case(load, pattern acces, RAM, and so on)! As a general rule any spcialize cache system(like OS cache in VM) is better compared with a general volum maneger cache sistem. Also the VM OS cache it very close to the source of data, and have a better chance to know what and when to cache the data.

So for this point of view, I think is better to use ARC only for metadata, so you will use not so much RAM(ARC), and then you can allocate supplimentary RAM for your VMs(better cache = better RAM usage). But also this ideea, is not 100% fail-safe!


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