Re: aic7xxx sets CDR offline, how to reset?

Doug Ledford
2002-09-04T10:48:06Z

On Wed, Sep 04, 2002 at 12:37:37PM +0200, Andries Brouwer wrote:
>
> The scsi error recovery has many bad properties, but one is its slowness.

This does not have to be this way. It is a solvable problem.

> Once it gets triggered on a machine with SCSI disks it is common to
> have a dead system for several minutes.

Yes, well, this too is solvable. It, in fact, reminds me that one of the
things I think needs added to the scsi host settings is a default timeout
value for typical devices. Something like adding a default_timeout value
to each Scsi_Device struct and allowing the scsi driver to modify the
value during the slave_attach() call. Then we can put the default timeout
on non-intelligent controllers to something sane while things like
MegaRAID controllers can keep their sky high timeout values.

> I have not yet met a situation
> in which rebooting was not preferable above scsi error recovery,
> especially since the attempt to recover often fails.

This, too, is solvable. It just requires that the scsi subsystem start
paying attention to *how* things fail and making the error handling code
smart enough to know when to retry things and when to just fail.

--
Doug Ledford <dledford@redhat.com> 919-754-3700 x44233
Red Hat, Inc.
1801 Varsity Dr.
Raleigh, NC 27606