Adding Drives to StorEdge A3000 (RSM-2000)

If you are adding drives to an A3000 from another A3000 you should add the
drives while the system is up and running.  It is recommended that you do NOT
cold-start the system.  If you do there is a possibility that the configuration
information on the new drives will confuse the controllers as to the
configuration of the Raid Module, which can result in an apparent loss of data
and/or LUN configuration.  This has only been confirmed when the number of drives
added is equal to or greater than the original number of configured drives, but
it has been reported that this has happened with as few as 5 additional drives.
If you do see a problem after adding drives (not seeing pre-existing LUNs) and
cold-starting the system, it is recommended that you remove the newly-added
drives, restart the system, then add them one at a time.  In tests run at
SunService, we were always able to recover the LUNS and associated data by
taking these steps.

This problem does not occur when the drives are added to the running system
(where they are just added to the "unused" drive group - after which it is safe
to cold-start the system).  Since hot-plugging is fully supported on the A3000,
this is the procedure recommended by SunService.

What is behind this is that certain configuration information (DACstore) is
written to all of the drives in a Raid Module (though only certain drives will
contain valid copies).  Removing drives from a LUN is not sufficient to remove
this information, though it will be overwritten when the drive is added to a
different raid module (at this time the only known way to clear the DACstore
entirely is to insert the drives in a Non-A3000 RSM or compatible trays and
format them).  The A3000 does a controlled startup, spinning up drives it knows
about first, and then new drives, presumably to avoid just this situation.
However it does appear that enough new drives added at one time will confuse the
controller.