Thank you! That looks like it would work. On Sat, Jul 11, 2020 at 11:58 AM Andrei Borzenkov <arvidjaar@xxxxxxxxx> wrote: > > 11.07.2020 17:42, Stirling Westrup пишет: > > I have a BTRFS built with two devices md0 and md1 on a server. I wish > > to move as much data as will fit from md0 to md1, but I cannot figure > > out a balance command that will do that. > > > > My use case is a file server with a fixed number of hard drive slots > > and two raids. md0 is a raid using most of the slots with small > > drives, and md1 is a raid using the remaining slots with large drives. > > I'm trying to shrink md0, so I can remove some small drives and put in > > new large drives to add to md1. > > > > I have read the notes on the balance command several times but I can't > > figure out how to get it to do what I want, if it's even possible. > > > > You should be able to shrink md0 which will relocate data beyond new > size to another device(s). See example in btrfs-filesystem: > > > $ btrfs filesystem resize -1G /path > > $ btrfs filesystem resize 1:-1G /path > > Shrink size of the filesystem’s device id 1 by 1GiB. The first > syntax expects a > device with id 1 to exist, otherwise fails. The second is > equivalent and more > explicit. For a single-device filesystem it’s typically not > necessary to specify the > devid though. > > > This assumes you are using single or dup profiles, as other profiles > require at least two devices anyway and you may not be able to shrink > md0 too far. -- Stirling Westrup (he/him) Programmer, Entrepreneur. http://www.linkedin.com/in/swestrup (+1) 514-626-0928
