Am Sat, 17 May 2014 08:08:17 +0800 schrieb William Kenworthy <[email protected]>:
> On 17/05/14 04:15, Marc Joliet wrote:
> > So, a week has passed since my conversion to btrfs.
> >
> > So far there seem to have been no problems, my system has been running as if
> > nothing has changed :) . Which, as a friend pointed out, is how it should
> > be.
> >
> > I don't think there is anything particularly interesting to mention in
> > addition
> > to what I already wrote. I can just say that I think the effort was worth
> > it.
> >
> > The one thing that I can tell from reading the past two weeks of the btrfs
> > ML
> > is that the 3.15 Linux kernel series will contain lots of bug fixes (for
> > example in balancing, error handling, and send/receive), and that I will
> > want
> > to use that sooner rather than later. Of course, the severity of the
> > problems
> > varies, and a lot are triggered under odd, or at least uncommon,
> > circumstances.
> > Still, its worth paying attention to.
> >
> > Also, a lot of problem reports I saw came from people using other volume
> > management below btrfs, interestingly enough.
> >
> > As for the future, I think I will wait a while, and get some experience with
> > btrfs first. I suspect that by the time btrfs supports swap files, it will
> > be
> > stable enough that I would consider converting my SSD to also use btrfs
> > anyway :) . Possibly before that, once I am fully convinced of btrfs'
> > stability, I will also convert my backup drive and switch to using snapshots
> > and send/receive to perform backups. Perhaps somebody will have written a
> > backup solution on top of snapshots by then.
> >
> > Have a nice weekend,
> >
>
> Don't forget to have a maintenance program - run a scrub regularly once
> a week or so - I have enough btrfs drives (22 qemu files, 4 WD Greens
> att) to see about one or two scrub fixable errors a week with no obvious
> cause, sometimes serious (in a critical file). My experience is that if
> you ignore these errors they seem to increase over time resulting in a
> crash and burn. Keep an eye on your logs as btrfs will list the errors
> there as well ("grep -i btrfs /var/log/messages"). For the ones scrub
> cant fix, delete the file and restore from backup. Errors that require
> off-line fixing (btrfsck) are the ones where I have lost file systems -
> though I have not seen this in the last 6 months.
I did not forget about scrubbing, though so far I have run them manually (once
on Monday after a weekend away from the computer, and once tonight, both
without error). Nevertheless, thanks for the reminder and extra info :) .
BTW: I came across an interesting tool called dstat (indirectly while looking
for which package contained iostat, which was mentioned on the btrfs ML). With
"dstat -df", you can monitor the I/O of each individual drive. It's fun
watching them be used in parallel :) .
Anyway, with dstat I discovered that my drives have noticeably different
throughput. Of course, I might have deduced that earlier:
# btrfs scrub status -d /home
scrub status for 472c9290-3ff2-4096-9c47-0612d3a52cef
scrub device /dev/sda (id 1) history
scrub started at Sat May 17 00:23:33 2014 and finished after 2536
seconds
total bytes scrubbed: 215.42GiB with 0 errors
scrub device /dev/sdb (id 2) history
scrub started at Sat May 17 00:23:33 2014 and finished after 3519
seconds
total bytes scrubbed: 216.32GiB with 0 errors
scrub device /dev/sdc (id 3) history
scrub started at Sat May 17 00:23:33 2014 and finished after 2346
seconds
total bytes scrubbed: 216.57GiB with 0 errors
scrub device /dev/sdd (id 4) history
scrub started at Sat May 17 00:23:33 2014 and finished after 2346
seconds
total bytes scrubbed: 215.68GiB with 0 errors
Boy, is sdb slow! I might replace it with sde, which is laying around as a
spare for now, and make sdb the spare instead.
> I am quite practised in restoring from backups because of btrfs :)
Haha :) .
--
Marc Joliet
--
"People who think they know everything really annoy those of us who know we
don't" - Bjarne Stroustrup
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