| > When my shared bus breaks up I still have a single
> point of failure as all my data for my services are
> on this shared bus (even if I would put my system disks
> on a different scsi-bus
To avoid a SPOF you should use LSM on TWO SCSI buses, but we
are speaking here of ALPHA SYSTEM scsi buses, NOT HSZ40 buses.
Moreover, if you place the system disk(s) on one HSZ40 (or even
on two HSZ40 mirrored by LSM), these system disks are not access
protected from the OTHER system(s) on the shared bus(es). So, any
root user on system A can write to system disk of system B.
In DECsafe services, the ASE AM drivers is taking care to place an
HARDWARE reservation bit on the disk(s) used by the service, so no
access violation is possible. This is NOT the case with the system
disk(s) placed on a shared bus (either behind an HSZ40 or not)
Regards, Manu.
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