Re: rescan scsi

Gerald Britton (
Fri, 20 Jun 1997 11:37:37 -0400 (EDT)

> Nevertheless, it is possible. There is no existing kernel code to support
> this. You CAN swap drives that are identical by dismounting the existing
> one, removing it, hooking up the other, then remounting (after fsck).
> Basically you are tricking the kernel into thinking it's the same drive.

echo "scsi add-single-device a b c d" >/proc/scsi/scsi
for scsi bus a, channel b, address c, lun d .. the kernel code is there
there is also a remove-single-device to deconfigure a device...
i required this when i was working with a zip drive using its parallel
port scsi driver.. though it should work for any scsi.

> I use this trick on my Suns. When I boot a Sun, I hook up an external
> tape drive. Once it is "up", I disconnect the drive (I only have 1 to share
> over a bunch of Suns).
> If I have to use the tape drive on a Sun, I reconnect it. It will work
> because the Sun "saw" it during initialization.

this isn't needed.. i've hot added many devices to suns... you simply get
the sun to rescan the scsi bus and rebuild the device information

/usr/sbin/tapes # /usr/sbin/disks if it's a disk that's added

this has worked great.. i've added several disks and tape drives using
these commands.

Gerald Britton