On Sun, 11 May 2014 16:11:56 Brendan Hide wrote: > On 2014/05/11 11:52 AM, Russell Coker wrote: > > On Sun, 11 May 2014, Russell Coker <russell@xxxxxxxxxxxx> wrote: > >> Below is the output of running a balance a few times on a 120G SSD. > > > > Sorry forgot to mention that's kernel 3.14.1 Debian package. > > Please send the output of the two following command: > btrfs fi df / #btrfs fi balance start -dusage=0 -musage=10 / Done, had to relocate 2 out of 107 chunks #btrfs fi balance start -dusage=0 -musage=10 / Done, had to relocate 2 out of 107 chunks #btrfs fi balance start -dusage=0 -musage=0 / Done, had to relocate 1 out of 107 chunks #btrfs fi balance start -dusage=0 -musage=0 / Done, had to relocate 1 out of 107 chunks #btrfs fi balance start -dusage=10 -musage=10 / Done, had to relocate 2 out of 107 chunks #btrfs fi balance start -dusage=10 -musage=10 / Done, had to relocate 2 out of 107 chunks #btrfs fi balance start -dusage=0 -musage=0 / Done, had to relocate 1 out of 107 chunks #btrfs fi balance start -dusage=0 -musage=0 / Done, had to relocate 1 out of 107 chunks #btrfs fi df / Data, single: total=100.47GiB, used=92.11GiB System, DUP: total=32.00MiB, used=20.00KiB Metadata, DUP: total=2.50GiB, used=1.50GiB #uname -a Linux workstation 3.14-1-amd64 #1 SMP Debian 3.14.2-1 (2014-04-28) x86_64 GNU/Linux Above is my workstation. Below is the server/workstation my wife uses. #btrfs fi balance start -dusage=0 -musage=0 / Done, had to relocate 0 out of 81 chunks #btrfs fi balance start -dusage=0 -musage=0 / Done, had to relocate 0 out of 81 chunks #btrfs fi balance start -dusage=1 -musage=1 / Done, had to relocate 1 out of 81 chunks #btrfs fi balance start -dusage=1 -musage=1 / Done, had to relocate 1 out of 81 chunks #btrfs fi balance start -dusage=1 -musage=1 / Done, had to relocate 1 out of 81 chunks #btrfs fi balance start -dusage=0 -musage=0 / Done, had to relocate 0 out of 81 chunks #btrfs fi df / Data: total=75.01GB, used=52.32GB System, DUP: total=32.00MB, used=16.00KB Metadata, DUP: total=2.50GB, used=1.52GB #uname -a Linux server 3.14-trunk-amd64 #1 SMP Debian 3.14.1-1~exp1 (2014-04-17) x86_64 GNU/Linux > This will give more information on your current chunk situation. I > suspect this is a case where a system chunk (which is included when > specifying metadata) that is not actually being relocated. This is a bug > that I believe was already fixed, though I'm not sure in which version. > > The pathological case is where you have a chunk that is 1% full and > *every* other in-use chunk on the device is 100% full. In that > situation, a balance will simply move that data into a new chunk (which > will only ever reach 1% full). Thus, all subsequent balances will > relocate that same data again to another new chunk. In that pathological case surely the correct thing to do is to not move that chunk. If moving a chunk doesn't achieve filesystem tuning goals (EG converting to a different RAID level) and doesn't result in a decrease of the number of chunks in use then surely there's no point to doing it. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/ -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
