On 2017年09月10日 01:44, Marc MERLIN wrote:
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?
Yes, the assumption that repair should be no faster than RO check is
correct.
Especially for clean fs, repair should just behave the same as RO check.
And I'll first submit a patch (or patches) to output the consumed time
for each tree, so we could have a clue what is going wrong.
(Digging the code is just a little too boring for me)
Thanks,
Qu
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.60TiB, used.54TiB
System, DUP: total2.00MiB, used=1.19MiB
Metadata, DUP: totalX.00GiB, used.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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