Re: lpfc SAN/SCSI issue

[brem belguebli <brem.belguebli@gmail.com>]

Hi James,

I could set lpfc_log_verbose on both HBA's to 4115, I hope it'll be high
enough to get interesting traces.

On Mon, 2010-04-26 at 23:52 +0200, brem belguebli wrote:
> Hi James,
> 
> On Mon, 2010-04-26 at 13:50 -0400, James Smart wrote:
> > Brem,
> > 
> > I'm not understanding you.
> > 
> > 
> > brem belguebli wrote: 
> > > We have sg3_utils installed , and I think we ran sg_verify on one or
> > > 2
> > > unresponsive /dev/sd and it didn't give the hand back.
> > >   
> > what do you mean "give the hand back" ?    was the operation
> > successful or not ?
> > 
> When I say it didn't give the hand back, I mean the one or 2 processes
> got stuck in D state, thus not returning success .
> > > It was exactly
> > > cd /sys/block
> > > for DEV in `ls -1d dev*`; do
> > > echo ${DEV}
> > >         dd if =/dev/${DEV} of=/dev/null bs=1024 count=1 &
> > >         echo
> > > done
> > > 
> > > And yes it really works, never seen any kind of preemption of DM-MP over
> > > direct sd access. I've cc'ed dm-devel may be some DM guru could give his
> > > opinion on this.
> > > 
> > > Next time, I'll use a sg_dd instead of dd, to bypass any cache effect
> > > (by the way, does VFS cache anything when addressing /dev/X devices ?)
> > >   
> > ok - by "works" means "dd successfully read 1 block from the device" -
> > right ?
> > 
> Yes, the devices on which dd was successful were the ones from FABRIC1,
> dd completed successfully by reading the first 1024 bytes to copy them
> to /dev/null
>   
> > > > The most interesting for the lpfc driver would be the lpfc module
> > > > parameter "lpfc_log_verbose=4115"
> > > > which turns on discovery log messages, els messages, link events, and
> > > > FCP i/o error messages.
> > > >     
> > > 
> > > As our DWDM ring switch is on the less optimal path, there will be a
> > > switch back to nominal soon.
> > > 
> > > I'll activate this log level on the HBA's and check the firmware
> > > versions you gave me .
> > >   
> > ok. I believe that the shost for the adapters in question, have a
> > sysfs variable for lpfc_log_verbose, that sets the log level on the
> > individual adapter. This would not require you to unload/reload the
> > driver to set the option.
> > 
> I'll tell you tomorrow (was off today) if the parameter exists for these
> HBA's.


> > > Hopefully, we will be able to provide you something deeper to
> > > investigate.
> > > 
> > > Brem
> > >   
> > 
> > ok.
> > 
> > -- james
> > 
> > 
> Thanks
> 
>