4 ms·
If you already have a spare disk installed doesn't it make more sense to just add it to pool anyway and just bump up the redundancy to Z2 or Z3?
by pedrocr 7y ago
If you already have a spare disk installed doesn't it make more sense to just add it to pool anyway and just bump up the redundancy to Z2 or Z3?
- gvb 7y agoThat is one of those Great Debates. If your spare disk is a "hot spare" where it is plugged in and powered up, yes. If your spare disk philosophy is "cold spare" where the drive is in a box on a shelf, probably not. Hot spares are faster and easier to turn into replacement drives but the "hot spare" is subject to usage-based (electrical, thermal, and mechanical) failure modes. For a given drive, the probability of failure is largely proportional to power-on hours[1]. Cold spares are not accumulating power-on hours so they likely won't fail while waiting to be used and presumably won't fail for quite some time after being installed as a replacement. [1] Intuitively, but hard to prove because of many confounding factors. Backblaze has the best drive failure rate data that I'm aware of: https://www.backblaze.com/b2/hard-drive-test-data.html https://www.backblaze.com/b2/hard-drive-test-data.html
- radiowave 7y agoYes, assuming: (1) You haven't already created the pool, as you can't alter an existing vdev from (e.g.) RAIDZ to RAIDZ2, and (2) your pool only contains a single vdev, or you're happy with an extra disk per vdev. Otherwise you're into dealing with spares, as gvb describes.