Kind of curious, how much disk space is required to run this pool?
Well the data/log disk is only 1TB, everything is backed up and archived off to another server that has 2TB
(and to my home also ... that has a 5TB disk that stores that data)
All raid1 of course.
That 1TB I keep at around 90% (and compession of each day is about 3% down to about 0.4% plus I discard old ckdb logs since they are duplicate of the ckpool logs - but they are kept on the backups)
The main system disk is raid1 SSD 240GB that's still well under 50% and grows ever so slowly
The main server itself has 24 CPU threads, 0 is always busy, the rest are mostly idle. Total usage is close to 5%
I recently heard from another pool owner how they considered raid1 a waste of time ... but disks fail often and having to recover everything when that happens is time consuming and a PITA - of course you also have active backup - but that should be a 2nd choice, not the only choice if a disk fails.
With raid1, if one disk fails, it keeps running and then you need to follow up fast and replace the failed disk just in case it's pal decides to die on you also.
If both go down, then you have to rely on your backups. But if only one, then the system just keeps going until you do a quick shutdown/replace/reboot for the dead disk. Optimal would be to have a 3rd disk instead of just 2, (like I do now at home thanks the the generosity of pool members when I had my double raid1 failure back in january) but maybe I'll consider that if the pool ever gets a lot bigger and I can afford it
With 3 disks, you keep the 3rd as an active spare and can swap it in immediately if one of the other 2 fails, so you always have 2 except during the swap in. You keep the 3rd one as a spare so that it's not in use and thus will have completely different life characteristics to the others.
... and anyone watching the pool - I restarted ckdb 45 minutes ago when doing a system update - it updated the main DB (postgresql) and that shutdown, restarted so ckdb had to do the same.