Running out of space... Suggestions?

[Constantin]

Given that a pool upgrade can simply noodle along in background, I’d simply replace one drive after the other.

 

[Etorix]

You can do 2 at a time with RAIDZ2, but you lose any safety margin: if you lose a disk while resilvering 2 others, you lose your pool.

Best of all: Replace drives with the old drive still in place. No loss of redundancy, Full safety margin. Can replace as many drives in one go as you want (or can), though ZFS may actually perform the operations in sequence rather than in parallel.

 

[AltecBX]

Good to know! In my case, I have 16 bays with 2 vdev with 6 drives in each. I have never ever taken a drive out and replaced it with a new one.
Every time I resilvered a drive I've always put 3 new drives in the unpopulated bays (1 port is not working) and just resilvered (replaced) from member drive from Disk 8 to Disk 14. Never had it occurred to me that I can just yank a drive and replace it with a new drive.

So in my case then, I can resilver 2 drives (per vdev) at a time as the 2 old drives will still be intact?

 

[Constantin]

There be dragons. No margin of safety. Go one at a time and enjoy doing something else.

 

[AltecBX]

Will do!
Thanks