From: Mike Christie <michaelc@cs.wisc.edu>
To: device-mapper development <dm-devel@redhat.com>
Subject: Re: multibus / failover and EMC CX600
Date: Wed, 17 Oct 2007 14:49:39 -0500 [thread overview]
Message-ID: <47166753.20400@cs.wisc.edu> (raw)
In-Reply-To: <471600F7.5090607@linpro.no>
Tore Anderson wrote:
> * Hannes Reinecke
>
>> That's the dev_loss_tmo setting. Just increase it to something to
>> your liking.
>
> Oh, sweet. This knob won't affect how long the layer will hold I/O
> before failing it (like lpfc_nodev_tmo), I assume? (I'm worried about
> it taking longer for dm-multipath to detect failed paths).
>
With newer versions of lpfc you can set
/sys/class/fc_rport/rportXYZ/fast_io_fail_tmo to a low value so that IO
is failed quickly, and then set the dev_loss_tmo to a high value so the
device is not removed quickly.
The only problem may be that there is a race where dm-multpiath could be
queueing IO to the scsi layer while the scsi layer is reporting a
failure. That IO that was getting queued will then sit in the scsi layer
until dev_loss_tmo fires. That is fixed with this patchset
http://marc.info/?l=linux-scsi&m=117399843216280&w=2
but I never finished testing it out.
prev parent reply other threads:[~2007-10-17 19:49 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-17 10:23 multibus / failover and EMC CX600 Gerald Nowitzky
2007-10-17 10:40 ` Tore Anderson
2007-10-17 11:08 ` Hannes Reinecke
2007-10-17 12:32 ` Tore Anderson
2007-10-17 14:48 ` Gerald Nowitzky
2007-10-17 16:01 ` Tore Anderson
2007-10-17 18:04 ` Gerald Nowitzky
2007-10-18 6:19 ` Hannes Reinecke
2007-10-18 6:55 ` Gerald Nowitzky
2007-10-18 7:12 ` Hannes Reinecke
2007-10-18 8:07 ` Gerald Nowitzky
2007-10-19 22:35 ` David Strand
2007-10-17 19:38 ` Gerald Nowitzky
2007-10-18 6:01 ` Tore Anderson
2007-10-18 6:19 ` Tore Anderson
2007-10-17 19:49 ` Mike Christie [this message]
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