On Tue, Dec 17, 2013 at 11:12:25PM -0500, Garry T. Williams wrote: > On 12-18-13 10:46:29 Anand Jain wrote: > > On 12/18/2013 10:03 AM, Garry T. Williams wrote: > > > I have been using btrfs for my /home partition on my home machine for > > > a few years now. I created the file system RAID1 using two disk > > > partitions. Recently I noticed btrfs fi df shows extra Data, System, > > > and Metadata allocations. And btrfs fi show indicates extra > > > allocations on one of my disk drives accounting for the 20 MiB > > > allocation in the df display. > > > > this is a known bug in mkfs.btrfs, the workaround for now is > > to run balance on FS having some data. so that unused group- > > profile will go away. > > Thanks. > > garry@vfr$ sudo btrfs balance start /home > Done, had to relocate 50 out of 50 chunks > garry@vfr$ sudo btrfs filesystem df /home > Data, RAID1: total=22.00GiB, used=21.02GiB > System, RAID1: total=32.00MiB, used=12.00KiB > System, single: total=4.00MiB, used=0.00 > Metadata, RAID1: total=1.00GiB, used=419.60MiB > > Hmmm. > > Well, it's better, but the extra allocation for System is baffling. I > believe that this happened sometime after creating the file system. It won't be spontaneously created -- it'll have been there since the beginning. The first system chunk is "special" and is skipped during balances, so it won't get cleaned up like this. > Also balance on a RAID1 file system with exactly two drives doesn't > make much sense to me. Why would any "chunks" have to be relocated? > I'm clearly missing something here. That's what balance does -- it rewrites every single piece of data on the filesystem. In this case, you could have used a filter to balance (and hence remove) only the single chunks: btrfs balance start -mprofiles=single -dprofiles=single -sprofiles=single /mountpoint Hugo. -- === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk === PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk --- One of these days, I'll catch that man without a quotation, --- and he'll look undressed.
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