Is adding device to subvolume the same as adding device to main filesystem in btrfs?

Question

When I add a device to a btrfs sub-volume with

btrfs device add /dev/sdb /path/to/subvolume

is the added device then only used for the sub-volume or is it used by the whole file-system ?

Or the question in the other way: Is it possible to add a device only to a sub-volume?

thanks!

Pilot6 · Accepted Answer · 2016-06-19 15:02:09Z

0

You can't add a device to a subvolume. You can add a device only to a filesystem.

But this command will work with any path to an object located on a btrfs filesystem.

And it looks like you do not quite understand what subvolume is. Adding a device to a subvolume makes no sense for me at all.

answered Jun 19, 2016 at 15:02

Pilot6

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okay, thanks! so, balancing with ´btrfs balance start -dconvert=raid1 -mconvert=raid1 /mnt´ works also with any path of the btrfs filesystem,right?
– oceanBT
Jun 19, 2016 at 17:09
Exactly. The object of the path should be on the correct FS. It does not matter which object. But I suggest using the mount point, just not to make a mistake.
– Pilot6
Jun 19, 2016 at 17:10

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