[dm-devel] [multipath] SCSI device capacity mess
christophe varoqui
christophe.varoqui at free.fr
Sat Oct 30 07:21:10 UTC 2004
> > I'm just saying we should stop on the first failed command (TUR) and not
> > retry to read all 64 sectors regardless. I can live with one error per
> > passive path, but 64 really kills the logs.
>
> That makes sense.
>
> What is the result of the TUR? I did not see any information about it in other posts in this thread.
>
the tur checker in multipath-tools report ghosts as failing.
> We should change state somehow if the TUR failed or was not ready, maybe
> call set_media_not_present(), or maybe change the sdev state to
> SDEV_OFFLINE - though that might cause extra logging.
>
> We might not normally every hit this since the scan (INQUIRY failure)
> would likely prevent the device from showing up at all.
scsi_id and INQUIRY succeed on ghost paths, which allow multipath to
group them with valid paths to the same LU.
> Plus, we only call sd_spinup_disk() during discovery and not on open,
> unlike the calls to sd_media_changed().
>
Would it be workable to add a scsi_devinfo flag for devices with ghosts.
If this flag is set and state is down, open calls sd_media_changed().
The multipath-tools and device-mapper will try as hard as possible to
avoid opening those device if not necessary, by grouping them in a low
priority path group.
regards,
--
christophe varoqui <christophe.varoqui at free.fr>
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