Hotplug SCSI disks + FC3 (2nd try)

[Rick Wagner]

On Tuesday 12 April 2005 11:21 am, T. Horsnell wrote:
> I'm still flailing around trying to understand why hotplugging
> my SCSI disks doesnt work. 2.6.10 kernel, and the disks are seen
> OK after a system boot. However any disks which are plugged
> in with the system running, dont seem to generate any hotplug
> activity (checked by modifying /bin/hotplug script to write to
> a file when it runs).
>
> Should hotplugging SCSI disks work with 2.6.10 kernel?
> If not, can anyone suggest how I might make the system see
> the new disks without rebooting? I've tried kudzu with no
> success (should *that* have worked?)

No.  Unless you use special hardware (hot plug chassis with enclosure 
management), the generic SCSI bus does not detect "plugs".  In addition, hot 
plugging can be dangerous.  If there is data I/O going on on the SCSI bus at 
the time you plug, you risk causing data corruption.  USUALLY this will be 
detected as a bus parity error, or other failures which get retried.  But if 
it doesn't...

> Is there some other way to force a SCSI-bus scan?
> (I see ../drivers/scsi/scsi_scan.c in the kernel source)

If you look at the SCSI how to (www.tldp.org), it makes reference to a 
command, something like "echo 'magic incantation' > /proc/scsi/...".  This 
causes the specified device to be added to the internal tables. I don't 
recall a rescan command, but I haven't looked in a while. If there is, it 
would most likely be a similar echo command.  It should be in the same SCSI 
how to.

> Thanks,
> Terry.

Your welcome,
	--rick