Re: Anyone tried out btrbk yet?

[Duncan <1i5t5.duncan@cox.net>]

Donald Pearson posted on Sat, 25 Jul 2015 08:27:03 -0500 as excerpted:

[Duncan wrote...]

>>>>> Also, FWIW, the btrfs quota subsystem increases snapshot management
>>>>> complexity dramatically, so if you're using that, aim for the low
>>>>> ends of the above recommendation if at all possible, and/or consider
>>>>> either turning off the quota stuff or using a filesystem other than
>>>>> btrfs, as in addition to the scaling issues, the quota management
>>>>> code has been a source of repeated bugs and isn't a feature I'd
>>>>> recommend relying on until it has at least several kernel cycles
>>>>> worth of trouble-free history behind it.

[Big intervening thread snip...]

> I can confirm that getting rid of the quotas fixed the issue for me.
> Just disabling quotas wasn't enough, I had to enable, delete all
> qgroups, reboot because disable was hung on one of the filesystems,
> then disable quotas.  Now when btrfs-cleaner runs it doesn't completely
> consume a core, I can see corresponding disk i/o, and the process goes
> away after a reasonable amount of time.

Thanks for the confirmation!

Good to have a recent and concrete report to point to, on the subject of 
btrfs and quotas, now.  Now I can at least say something like "we do have 
at least one report (4.1 timeframe) of snapshot deletion scaling or 
lockup issues where quotas was implicated -- after deleting qgroups and 
disabling quotas, the problem disappeared."

-- 
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