[systemd-devel] Slow startup of systemd-journal on BTRFS

[Duncan]

Goffredo Baroncelli posted on Mon, 16 Jun 2014 20:47:49 +0200 as
excerpted:

> The test #6 and #7 suggested that the fsync(2) amd posix_fallocate(3)
> calls aren't the root cause of the problem. Even without these the
> system.journal file still fragments.
> 
> [1] http://kreijack.blogspot.it/2014/06/btrfs-and-systemd-journal.html

Thanks for injecting some concrete facts in the form of test results into 
things. =:^)

So I was barking up the wrong tree with fallocate.

But I had the base problem correct -- fragmentation -- and good 
recommendations for working around it -- NOCOW and/or (auto)defrag.
(And for that matter, for those like me where /var/log is a dedicated 
partition, simply putting /var/log on something other than btrfs would 
nicely work around the issue too.

The experts are working on it now, so I'll step out for the most part as 
what else I could add at this point would be simply noise.  But I did 
consider it important to acknowledge that I had been wrong about the 
fallocate.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman