Hacker News Reader

Comment by JustSomeNobody | Hacker News Reader

So, what does one do if all they have laying around are mismatched drives?

You _can_ mix drives, but you'll get the worst from each. For each vdev (mirror pair, or raid stripe) writes will be limited by the slowest drive, and space will be limited by the smallest drive.

So if they're not highly mismatched, it can work ok. For example if you have a 1 TB and a 1.5 TB disk, but from the same series and as such with otherwise similar spec, it would work fine as a mirror vdev. Write speed will be limited to the slowest of them (most likely the 1 TB), and you'd only get 1 TB of available space, but it's more than nothing.

Ah, ok. I have 2 3TB and a 4TB running on a Proxmox v3 system. Was wanting to upgrade to Proxmox v5 and try ZFS.

The 4TB is a different make than the 2 3TB drives, though.

I've been running a mixed-make mirror array for half a year now. Like I said, speed is limited by slowest drive but apart from that it works just fine.

Thank you. I appreciate the info.

Note it's probably not a good idea (if possible) to mix 512 and 4096 byte sector drives in the same vdev.

If you create the pool with ashift=12, you're fine.

The only hazard is if you have an ashift=9 pool (the default, IIRC) and later add a 4096 byte sector drive, you might lose some write perf. It probably doesn't matter for homelab use.

There aren't many 512 byte drives any more. You'll be fine.

You can partition your drives based on the size of the smallest and make your pool on those partitions.

Reply on news.ycombinator.com