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Removing vdev from pool

I have a question about FreeNAS and perhaps zfs in general. I am having a hard time trying to find information on removing a vdev or a couple of vdevs from a pool. I have to think this can be done in order to retire old hardware or such but i cannot find an answer. My particular case is i have a server connected to two disk shelves. After getting alerts that one of the drives in one vdev was bad and swapping it out and still getting errors i was suspecting that something in the disk shelf itself was bad. So i wanted to remove it from my pool all together. I had enough space in the pool to cover the removal but could not find the “how to”. This disk shelf was setup with three vdevs, 4 drives each in a RAIDZ1. So replacing disk is easy enough, swap the disk and resilver, but how do you remove a disk shelf or server from the pool in order to replace or upgrade hardware? This project is for a home use setup so i do not have a budget to replace whole units at once as i am already trying the best way to add minimal drives at a time to expand. Thank you for your time.

As Ive heard… you dont remove vdevs.

You can replace the devices in a vdev.

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This post says you can (edit, at least for mirrors): http://blog.moellenkamp.org/archives/50-How-to-remove-a-top-level-vdev-from-a-ZFS-pool.html

Haven’t tried it myself but I’m curious since I would like to free a raidz vdev to add the drives to another raidz2 vdev and don’t have enough storage to migrate at the moment.

EDIT; No nx2l is correct. The “new” feature of ZFS does not help us and doesn’t even seem to work right.

“However, removing toplevel data vdevs in a RAID-Z pool is unsupported.”
https://docs.oracle.com/cd/E37838_01/html/E61017/remove-devices.html

And problems with “remove” even used as advertised
https://www.ixsystems.com/community/threads/zfs-device-removal-what-about-pools-with-raidz-vdevs.69206/

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