that are on a CISS bus to be exported up to CAM and made available as normal
devices. This will typically add one or two buses to CAM, which will be
numbered starting at 32 to allow room for CISS proxy buses. Also, the CISS
firmware usually hides disk devices, but these can also be exposed as 'pass'
devices if you set the hw.ciss.expose_hidden_physical tunable.
Sponsored by: Tape Laboratories, Inc.
MFC After: 3 days
Logical volumes on these devices show up as LUNs behind another
controller (also known as proxy controller). In order to issue
firmware commands for a volume on a proxy controller, they must be
targeted at the address of the proxy controller it is attached to,
not the Host/PCI controller.
A proxy controller is defined as a device listed in the INQUIRY
PHYSICAL LUNS command who's L2 and L3 SCSI addresses are zero. The
corresponding address returned defines which "bus" the controller
lives on and we use this to create a virtual CAM bus.
A logical volume's addresses first byte defines the logical drive
number. The second byte defines the bus that it is attached to
which corresponds to the BUS of the proxy controller's found or the
Host/PCI controller.
Change event notification to be handled in its own kernel thread.
This is needed since some events may require the driver to sleep
on some operations and this cannot be done during interrupt context.
With this change, it is now possible to create and destroy logical
volumes from FreeBSD, but it requires a native application to
construct the proper firmware commands which is not publicly
available.
Special thanks to John Cagle @ HP for providing remote access to
all the hardware and beating on the storage engineers at HP to
answer my questions.
