> -----Original Message----- > From: linux-btrfs-owner@xxxxxxxxxxxxxxx [mailto:linux-btrfs- > owner@xxxxxxxxxxxxxxx] On Behalf Of Goffredo Baroncelli > Sent: Saturday, 29 April 2017 3:05 AM > To: Chris Murphy <lists@xxxxxxxxxxxxxxxxx> > Cc: Btrfs BTRFS <linux-btrfs@xxxxxxxxxxxxxxx> > Subject: Re: btrfs, journald logs, fragmentation, and fallocate > > > In the past I faced the same problems; I collected some data here > http://kreijack.blogspot.it/2014/06/btrfs-and-systemd-journal.html. > Unfortunately the journald files are very bad, because first the data is > written (appended), then the index fields are updated. Unfortunately these > indexes are near after the last write . So fragmentation is unavoidable. Perhaps a better idea for COW filesystems is to store the index in a separate file, and/or rewrite the last 1 MB block (or part thereof) of the data file every time data is appended? That way the data file will use 1MB extents and hopefully avoid ridiculous amounts of metadata. Paul. ��.n��������+%������w��{.n�����{����n�r������&��z�ޗ�zf���h���~����������_��+v���)ߣ�
