Changing fibre channel timeout values

[Paulo A G Fessel]

We are having performance problems with an Informix database in HP-UX 11.00 on an N-Class machine, connected to an EMC Symmetrix frame through an A6826A Tachyon FC Dual adapter.

For other boards - particularly Emulex ones - I know that it's possible to change timeout values of the FC driver. EMC frequently suggests to change these values when connecting to a Symmetrix frame. Problem is, I can't find where to configure these timeouts for Tachyon FC driver.

The EMC personnel said us that the timeout value is set to its default - 30s, according to EMC people - and they said us to change this to 90s.

As I haven't found nothing to configure in the FC driver, I'd like to know if issuing a pvchange -t 90 /dev/dsk/ would have an equivalent effect.

TIA,
Paulo Fessel

[Jeff Schussele · Accepted solution]

Hi Paulo,

Yes the pvchange -t is one way to alter the timeout value.

lvchange -t is another.

You can't use any FC utilities to do this, it's a function of LVM.

HTH,
Jeff

[Paulo A G Fessel]

Thanks Jeff.

Are these changes

1) immediate? (that is, no need for reboot)
2) permanent? (that is, persistent among reboots)


Also, SCSI timeouts are configurable? I looked at Kernel Tunables Guide, but I've seen only AIO parameters, not SCSI ones.

TIA
Paulo Fessel

[Robert-Jan Goossens]

Hi,

pvchange and lvchange do not need a reboot and they are permanent.

Regards,
Robert-Jan.