More details on the issue and a complete explantion you can find here: http://marc.merlins.org/perso/btrfs/post_2014-05-04_Fixing-Btrfs-Filesystem-Full-Problems.html and (Help! I ran out of disk space! ) https://btrfs.wiki.kernel.org/index.php/FAQ#Help.21_I_ran_out_of_disk_space.21
And an explantion for the "dlimit" solution: Quote From: Uncommon solutions for BTRFS (http://blog.schmorp.de/2015-10-08-smr-archive-drives-fast-now.html) > For my purposes, I define internal fragmentation as space allocated but not > usable by the filesystem. In BTRFS, each time you delete files, the space > used by those files cannot be reused for new files automatically. > It's not a hard requirement to do this maintenance regularly, but doing it > regularly spares you waiting for hours when the disk is full and you need to > wait for a balance clean up command - and of course also reduces the number > of > times you get unexpected disk full errors. As a side note, this can also > be useful to prolong the life of your SSD because it allows the SSD to reuse > space not needed by the filesystem (although there is a trade-off, frequent > balancing is bad, no balancing is bad, the sweet spot is somewhere in > between). 2016-09-20 10:20 GMT+02:00 Peter Becker <floyd....@gmail.com>: > Normaly total and used should deviate us a few gb. > depend on your write workload you should run > > btrfs balance start -dusage=60 /mnt > > every week to avoid "ENOSPC" > > if you use newer btrfs-progs who supper balance limit filters you should run > > btrfs balance start -dusage=99 -dlimit=10 /mnt > > every 3 hours. > > This will balance 2 Blocks (dlimit=10; corresponds to 10 gb) with are > not filled full into new blocks. You could/should adjust the intervall > and the limit-filter depend on your write workload. > For example if you write (change files + new files) only 10GB a day it > will be enough to run this ever night. > The last option completly avoid the ENOSPC issue but produce aditional > workload for your harddrives. > > Note: you should avoid making snapshots during balance. Use a simple > lock-mechanic for that. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
