ZFS What happens when 1 drive of a 3 drive zpool goes down?

azathoth

azathoth

What happens?
Say 3 usb drives, 5t and 2x4t
13T total, and say 6T of it used.
Do you lose everything?
Assuming 1 drive just had the usb cable kicked out, can you plug it back in and recover?
 
Assuming that the two 4TB drives are in a mirror and the 5TB drive is its own distinct vdev, then if that 5TB drive fails you would lose everything. Single-disk vdevs are always a bad idea.

The reason is that ZFS tries to spread data and metadata evenly across all devices, including metadata about the pool itself. If a non-redundant virtual device dies, you lose both the files stored on that virtual device and some metadata about the pool itself. The pool can't properly function or be reconstructed without all that metadata intact, so you'd lose everything else in the pool as well.
 
ANOKNUSA said:
Assuming that the two 4TB drives are in a mirror and the 5TB drive is its own distinct vdev, then if that 5TB drive fails you would lose everything. Single-disk vdevs are always a bad idea.

The reason is that ZFS tries to spread data and metadata evenly across all devices, including metadata about the pool itself. If a non-redundant virtual device dies, you lose both the files stored on that virtual device and some metadata about the pool itself. The pool can't properly function or be reconstructed without all that metadata intact, so you'd lose everything else in the pool as well.
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No no the 3 drives are all 1 pool.

What happens when I plug back in the drive that got unplugged?
 
If this pool has 3 top-level vdevs and no redundancy, then losing any drive will kill the pool, losing all data.

If a drive drops off the system and gets reenabled right away, you may get lucky and everything will continue as per normal.

More likely, though, is that the pool is dead.

There's very few legitimate reasons to run a non-redundant ZFS pool.
 
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