3 ms·
> An important note is that you CANNOT add extra disks to an existing VDEV. Not true for mirror vdev, but you don’t get the added capacity. You may add vdevs l
by eatbitseveryday 4y ago
> An important note is that you CANNOT add extra disks to an existing VDEV.
Not true for mirror vdev, but you don’t get the added capacity. You may add vdevs later, however.
Also some good arguments are made for using mirror vdevs over RAID-Z [1]. The extra space afforded by a 1:3 RAIDZ compared to 1:2 mirror isn’t much. Given the performance gain over a mirror resilvering and reduced recovery time, I prefer mirroring.
[1] https://jrs-s.net/2015/02/06/zfs-you-should-use-mirror-vdevs-not-raidz/ https://jrs-s.net/2015/02/06/zfs-you-should-use-mirror-vdevs...
- Nursie 4y agoPretty sure this is no longer true for RAIDZ as well, though the space usage is non-optimal at first, until files are read/written enough (it fixes itself over time). No idea if this has filtered through to mainstream release yet, but it was announced almost 18 months ago. (Edit — AFAICT it is still in the pipeline but not yet quite released)
- eatbitseveryday 4y ago> No idea if this has filtered through to mainstream release yet, but it was announced almost 18 months ago. What was announced?
- Nursie 4y agoThat you will, when the PR is considered fully stable and good to go, be able to add drives to a RAIDZ vdev. Here we are - https://arstechnica.com/gadgets/2021/06/raidz-expansion-code-lands-in-openzfs-master/amp/ https://arstechnica.com/gadgets/2021/06/raidz-expansion-code...
- reportingsjr 4y agoWhen I built my home storage server I made a mistake, and thought I could fit an additional drive, but I ran out of SATA ports. I kept the extra drive as a cold swap and just set up a raidz array. I ended up freeing up that SATA port I needed, but I'm waiting just a bit longer to expand ZFS on to that last drive so this code can get juuusstt a bit more testing!