freebsd stable - Oct 2016 - zfs, a directory that used to hold lot of files and listing pause

Do you have atime enabled for the relevant volume?

If so disable it and see if that helps:
zfs set atime=off <volume>

     Regards
     Steve

On 20/10/2016 14:47, Eugene M. Zheganin wrote:
> Hi.
>
> I have FreeBSD 10.2-STABLE r289293 (but I have observed this situation 
> on different releases) and a zfs. I also have one directory that used 
> to have a lot of (tens of thousands) files. I surely takes a lot of 
> time to get a listing of it. But now I have 2 files and a couple of 
> dozens directories in it (I sorted files into directories). 
> Surprisingly, there's still a lag between "ls" and an output:
>
>
> ===Cut==>
> # /usr/bin/time -h ls
> .recycle        2016-01         2016-04         2016-07 
> 2016-10         sort-files.sh
> 2014            2016-02         2016-05         2016-08 
> ktrace.out      sort-months.sh
> 2015            2016-03         2016-06         2016-09 
> old             sounds
>         5.75s real              0.00s user              0.02s sys
>
> ===Cut==>
>
> I've seen this situation before, on other servers, so it's not the 
> first time I encounter this. However, it's not 100% reproducible (I 
> mean, if I fill the directory with dozens of thousands of files, I 
> will not certainly get this lag after the deletion).
>
> Has anyone seen this and does anyone know how to resolve this ? It's 
> not critical issue, but it makes thing uncomfortable here. One method 
> I'm aware of: you can move the contents of this directory to some 
> other place, then delete it and create again. But it's kind of a nasty 
> workaround.
>
>
> Thanks.
>
> Eugene.
>
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Hi.

On 20.10.2016 21:17, Steven Hartland wrote:
> Do you have atime enabled for the relevant volume?
I do.
>
> If so disable it and see if that helps:
> zfs set atime=off <volume>
>
Nah, it doesn't help at all.

Thanks.
Eugene.