[OmniOS-discuss] iscsi timeouts

[Tobias Oetiker]

Hi Nld,

Today Narayan Desai wrote:

> Sorry, I should have given the requisite "yes, I know that this is a recipe
> for sadness, for I too have experienced said sadness".
>
> That said, we've seen this kind of problem when there was a device in a
> vdev that was dying a slow death. There wouldn't necessarily be any sign,
> aside from insanely high service times on an individual device in the pool.
> From this, I assume that ZFS is still sensitive to variation in underlying
> drive performance.
>
> Tobi, what do your drive service times look like?
>  -nld

the drives seem fine, smart is not reporting anything out of the
ordinary and also iostat -En shows 0 on all counts

I don't think it is a disk issue, but rather something connected
with the network ...

On times the machine becomes unreachable for some time, and then it
is possible to login via console and all seems well internally.
setting the network interface offline and then online again using
the dladm tool brings the connectivity back immediatly. waiting
helps as well ... since the problem sorts itself out after a few
seconds to minutes ...

we just had another 'off the net' periode for 30 minutes

unfortunately omnios itself does not seem to realize that something
is off, at least dmesg does not show any kernel messages about this
problem ...

we have several systems running on the S2600CP MB ... this is the
only one showing problems ...

the next thing I intend todo is to upgrade the MB firmware since I
found that this box has an older version than the other ones ...

System Configuration: Intel Corporation S2600CP
BIOS Configuration: Intel Corp. SE5C600.86B.01.06.0002.110120121539 11/01/2012

other ideas, most welcome !

cheers
tobi
>
>
> On Tue, Jan 21, 2014 at 7:58 AM, Dan McDonald <danmcd at omniti.com> wrote:
>
> >
> > On Jan 21, 2014, at 7:21 AM, Narayan Desai <narayan.desai at gmail.com>
> > wrote:
> >
> > > We've seen problems like this when we have a SATA drive in a SAS
> > expander that is going out to lunch. Are there any drives showing errors in
> > iostat -En? or any drive timeout messages in the ring buffer?
> >
> > Generally speaking --> you use a SATA drive in a SAS expander at your own
> > risk.  I used to be at Nexenta, and they would not support customers who
> > deployed SATA drives on SAS expanders.  These days, the price delta between
> > SAS and SATA (for enterprise) is small enough to be worth it for the
> > headaches you avoid.
> >
> > Dan
> >
> >
> >
>

-- 
Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
http://it.oetiker.ch tobi at oetiker.ch ++41 62 775 9902 / sb: -9900