taskqueue timeout

[Steve Bertrand]

Matthew Dillon wrote:

>     This issue is vexing a lot of people.

Heh... I can appreciate this. I would like someone to inform me that 
this can't be guaranteed to be a ZFS problem... if I can get 
confirmation that others have this issue aside from ZFS, I would feel 
content.

>     Setting the timeout to 30 will not effect performance, but it will
>     cause a 30 second delay in recovery when (if) the problem occurs.
>     i.e. when the disk stalls it will just sit there doing nothing for
>     30 seconds, then it will print the timeout message and try to recover.

If I have the timeout at >= 30 and the issue still occurs, the problem 
must be elsewhere.

>     It occurs to me that it might be beneficial to actually measure the
>     disk's response time to each request, and then graph it over a period
>     of time.  Maybe seeing the issue visually will give some clue as to the
>     actual cause.

I am interested in following through with this, but can't do it on my 
own. I'm willing to dedicate the box and bandwidth to anyone who can 
legitimately test this as you state. ie: I need either guidance or 
assistance.

This box is ready for the taking. Beyond this box, I can provide 
legitimate parties other network resources to produce a consistent flow 
of data to ensure the ability to easily reproduce the issue locally, on 
demand.

Steve