ZFS and large directories - caveat report

[Ivan Voras]

On 21 July 2011 22:31, Luiz Otavio O Souza <lists.br at gmail.com> wrote:
> On Jul 21, 2011, at 5:04 PM, Ivan Voras wrote:
>
>> The "load.." lines in between are  me hitting Ctrl-T for process info.
>> Observe almost 20 seconds delay in the middle of "ls"!
>
> What do you have for the the first column on gstat (L(q) values) ?
>
> The server in question is a DELL R710 that comes as a poor choice on bought (nobody notice the SATA disks until the server was installed - then it was too late for a exchange).
>
> It was a lot worse at beginning and adding the following lines (to /boot/loader.conf) did help a little bit (it is usable now, even when it is fully loaded by find requests - usable but not normal -).
>
> vfs.zfs.vdev.min_pending=1
> vfs.zfs.vdev.max_pending=1
>
> Not sure if this will help with your hardware, but you can give it a try if you're seeing high values for the L(q) column.

Thanks for the tip but no, device queues are very short (1-2).