Re: Linux Cluster using shared scsi

James Bottomley
2001-05-03T13:52:46Z

There is another nasty in multi-port arrays that I should perhaps point out:
a bus reset isn't supposed to drop the reservation if it was taken on another
port. A device or LUN reset will drop reservations on all ports. This
behaviour, although clearly mandated by the SCSI-3-SPC, is rather patchily
implemented in arrays and I have seen some multi-port arrays that will,
illegally, drop reservations on all ports on receipt of a bus reset.

Unfortunately, most Linux SCSI drivers won't issue device resets on command,
they'll only issue bus resets, so it is possible to get into a situation where
you cannot break a reservation belonging to a dead machine, if you set up a
point-to-point cluster rather than a true shared-scsi one.

James