> >
> > Well, first you have to explain what the MULTI_LUN thing does, because I
> > have no idea. However, from XFS's point of view, a device is a device
> > is a device - unless it is LVM. There are some differences there in
> > terms of how we do disk I/O to the log.
>
>
> >From kernel help
> "If you have a SCSI device that supports more than one LUN (Logical
> Unit Number), e.g. a CD jukebox, and only one LUN is detected, you
> can say Y here to force the SCSI driver to probe for multiple LUNs.
> A SCSI device with multiple LUNs acts logically like multiple SCSI
> devices. The vast majority of SCSI devices have only one LUN, and
> so most people can say N here and should in fact do so, because it
> is safer. "
>
> MULTI_LUN is using to probe multi device on one scsi channel.
Ah, OK, so this is a total red herring then because there is nothing
special about the devices themselves, or how they are accessed once
you find them.
Can you describe the exact configuration of the volume you are making
the filesystem on when you get the slow performance.
Steve
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