Add a single miror disk to a 2 disk stripe

[killed2]

Hi.

I previously had a data pool with 2 8TB drives in a mirror. As i was at 85% capacity, i bought a single 18TB disk and wanted to extend the pool.
I removed the mirror disk and added it as a stripe for more storage and now i wanted to add the new 18TB to mirror the 2 disk stripe as a whole.
That dooesn't seem to work and i feel really stupid that i did not ask about this before converting my pool.
Is this possible to achieve? I really don't know how to continue -.-

 

[danb35]

wanted to add the new 18TB to mirror the 2 disk stripe as a whole.

This isn't an option with ZFS. You could partition the disk, and use one partition to mirror one disk, and the other partition to mirror the other disk, but that'd all be at the CLI and really isn't a good idea.

 

[Arwen]

Actually @killed2 can have ZFS "remove" the 8TB disk as long as their is enough free space on the 18TB disk. Then, that 8TB disk can be physically removed making the slot available for the second 18TB disk. And if their is enough slots, just Mirror both single disks to their respective partners.

To be fair to @danb35, ZFS remove is a relatively newish feature, (well, a few years old), so it's not yet in the mind set of some ZFS users. And ZFS remove does not work for RAID-Zx or dRAID vDevs.

This does not have a date, but it is around 2015/01/15 that the very initial work at device removal was added. It was many years later before the feature was considered stable. And more time after that, until it was included into TrueNAS.

OpenZFS Device Removal

A few of weeks ago, Matt and I integrated OpenZFS device removal into the Delphix downstream repository of Illumos...

www.delphix.com