Re: How to remove missing device on RAID1?

[Dmitry Katsubo <dmitry.katsubo@gmail.com>]

On 2015-10-21 00:40, Henk Slager wrote:
> I had a similar issue some time ago, around the time kernel 4.1.6 was
> just there.
> In case you don't want to wait for new disk or decide to just run the
> filesystem with 1 disk less or maybe later on replace 1 of the still
> healthy disks with a double/bigger sized one and use current/older
> kernel+tools, you could do this (assuming the filesystem is not too
> full of course):
> - mount degraded
> - btrfs balance start -f -v -sdevid=1 -sdevid=1 -sdevid=1 <mountpoint>
>   (where missing disk has devid 1)

Am I right that one can "btrfs dev delete 1" after balance succeeded?

> After completion the (virtual/missing) device shall be fully unallocated
> - create /dev/loopX with sparse file of same size as missing disk on
> some other filesystem
> - btrfs replace start 1 /dev/loopX <mountpoint>
> - remove /dev/loopX from the filesystem
> - remount filesystyem without degraded
> And remove /dev/loopX

If would be nice if btrfs allows to delete device and perform rebalance
automatically (provided that left devices still have enough space to
sustain raidX prerequisite).

-- 
With best regards,
Dmitry