Re: btrfs check --repair now runs in minutes instead of hours? aborting

[Marc MERLIN <marc@merlins.org>]

So, should I assume that btrfs progs git has some issue since there is
no plausible way that a check --repair should be faster than a regular
check?

Thanks,
Marc

On Tue, Sep 05, 2017 at 07:45:25AM -0700, Marc MERLIN wrote:
> On Tue, Sep 05, 2017 at 04:05:04PM +0800, Qu Wenruo wrote:
> > > gargamel:~# btrfs fi df /mnt/btrfs_pool1
> > > Data, single: total\x10.60TiB, used\x10.54TiB
> > > System, DUP: total2.00MiB, used=1.19MiB
> > > Metadata, DUP: totalX.00GiB, used\x12.69GiB
> > 
> > Wait for a minute.
> > 
> > Is that .69GiB means 706 MiB? Or my email client/GMX screwed up the format
> > (again)?
> > This output format must be changed, at least to 0.69 GiB, or 706 MiB.
>  
> Email client problem. I see control characters in what you quoted.
> 
> Let's try again
> gargamel:~# btrfs fi df /mnt/btrfs_pool1
> Data, single: total=10.66TiB, used=10.60TiB      => 10TB
> System, DUP: total=64.00MiB, used=1.20MiB        => 1.2MB
> Metadata, DUP: total=57.50GiB, used=12.76GiB     => 13GB
> GlobalReserve, single: total=512.00MiB, used=0.00B  => 0
> 
> > You mean lowmem is actually FASTER than original mode?
> > That's very surprising.
>  
> Correct, unless I add --repair and then original mode is 2x faster than
> lowmem.
> 
> > Is there any special operation done for that btrfs?
> > Like offline dedupe or tons of reflinks?
> 
> In this case, no.
> Note that btrfs check used to take many hours overnight until I did a
> git pull of btrfs progs and built the latest from TOT.
> 
> > BTW, how many subvolumes do you have in the fs?
>  
> gargamel:/mnt/btrfs_pool1# btrfs subvolume list . | wc -l
> 91
> 
> If I remove snapshots for btrfs send and historical 'backups':
> gargamel:/mnt/btrfs_pool1# btrfs subvolume list . | grep -Ev '(hourly|daily|weekly|rw|ro)' | wc -l
> 5
> 
> > This looks like a bug. My first guess is related to number of
> > subvolumes/reflinks, but I'm not sure since I don't have many real-world
> > btrfs.
> > 
> > I'll take sometime to look into it.
> > 
> > Thanks for the very interesting report,
> 
> Thanks for having a look :)
> 
> Marc
> -- 
> "A mouse is a device used to point at the xterm you want to type in" - A.S.R.
> Microsoft is to operating systems ....
>                                       .... what McDonalds is to gourmet cooking
> Home page: http://marc.merlins.org/                         | PGP 1024R/763BE901
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-- 
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems ....
                                      .... what McDonalds is to gourmet cooking
Home page: http://marc.merlins.org/                         | PGP 1024R/763BE901