John Ettedgui wrote on 2015/07/29 18:55 +0000:
Hello,
I have the same issue and would like to add myself to this thread.
My btrfs partition is about 10tb on top of lvm2 and has been taking about a minute to mount in the past few months.
Qu Wenruo <quwenruo <at>cn.fujitsu.com <http://cn.fujitsu.com>> writes:
Quite common, especial when it grows large.
But it would be much better to use ftrace to show which btrfs operation
takes the most time.
I have got a trace file running this command:
trace-cmd record -e btrfs mount <PARTITION>
Since it is fairly big for an email I have gzipped it.
Thanks!
John
Hi John,
Thanks for the trace output.
But it seems that, your root partition is also btrfs, causing a lot of
btrfs trace from your systemd journal.
Would you mind re-collecting the ftrace without such logging system
caused btrfs trace?
BTW, although I'm not quite familiar with ftrace, would you please
consider collect ftrace with function_graph tracer?
That would help a lot to find which takes the most time.
But it may trace too much things and maybe hard to read.
Thanks,
Qu
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