On Tue, Sep 24, 2019 at 7:42 AM <hoegge@xxxxxxxxx> wrote: > > Sorry forgot root when issuing commands: > > ash-4.3# btrfs fi show > Label: '2016.05.06-09:13:52 v7321' uuid: 63121c18-2bed-4c81-a514-77be2fba7ab8 > Total devices 1 FS bytes used 4.31TiB > devid 1 size 9.97TiB used 4.55TiB path /dev/mapper/vg1-volume_1 OK so you can do # pvs And that should show what makes up that logical volume. And you can also double check with # cat /proc/mdstat > Data, single: total=4.38TiB, used=4.30TiB > System, DUP: total=8.00MiB, used=96.00KiB > System, single: total=4.00MiB, used=0.00B > Metadata, DUP: total=89.50GiB, used=6.63GiB > Metadata, single: total=8.00MiB, used=0.00B > GlobalReserve, single: total=512.00MiB, used=0.00B Yeah there's a couple of issues there that aren't problems per se. But with the older kernel, it's probably a good idea to reduce the large number of unused metadata block groups: # btrfs balance start -mconvert=dup,soft /mountpoint/ ##no idea where the mount point is for your btrfs volume that command will get rid of those empty single profile system and metadata block groups. It should complete almost instantly. # btrfs balance start -musage=25 /mountpoint That will find block groups with 25% or less usage, move and consolidate their extents into new metadata block groups and then delete the old ones. 25% is pretty conservative. There's ~89GiB allocated to metadata, but only ~7GiB is used. So this command will find the tiny bits of metadata strewn out over those 89GiB and consolidate them, and basically it'll free up a bunch of space. It's not really necessary to do this, you've got a ton of free space left, only 1/2 the pool is used 9.97TiB used 4.55TiB > > Synology indicates that BTRFS can do self healing of data using RAID information? Is that really the case if it is not a "BTRFS raid" but a MD or SHR raid? Btrfs will only self heal the metadata in this file system, because there's two copies of metadata. It can't do self heal on data. That'd be up to whatever lower layer is providing the RAID capability and whether md or lvm based, it depends on the drive itself spitting out some kind of discrete read or write error in order for md/lvm to know what to do. There are no checksums available to it, so it has no idea if the data is corrupt. It only knows if a drive complains, it needs to attempt reconstruction. If that reconstruction produces corrupt data, Btrfs still detects it and will report on it, but it can't fix it. -- Chris Murphy
