HP XP7 Storage - Manual (Page 18)

Figure 2 Current assignment sequence
Figure 3 Improved assignment sequence
The command device performs the assignment of an instance through TWO phases that have
"temporary allocation (1 0)" and "actual allocation (1 1)" to the instance assignment table.
If the command device is attacked, the instance assignment table is filled with "temporary allocation
(1 0)" status. After that, the command device will detect a fault of full space as the instance
assignment, clear up all "temporary allocation (1 0)", and then reassign the required instance
automatically.
This does not require a service representative to switch the command device "OFF/ON" to clear
up the instance table.
Verifying the RAID Manager instance number
RAID Manager provides a way to verify the number of "temporary allocations (1 0)" and "actual
allocations (1 1)" on the instance table so that you can confirm validity of the RAID Manager
instance number in use. The horcctl -DI command shows the number of RAID Manager
instances since HORCM was started as follows.
Example without command device security:
# horcctl -DI
Current control device = /dev/rdsk/c0t0d0 AI = 14 TI = 0 CI = 1
Example with command device security:
# horcctl -DI
Current control device = /dev/rdsk/c0t0d0 * AI = 14 TI = 0 CI = 1
AI : NUM of actual instances in use TI : NUM of temporary instances in RAID CI : NUM of instances
using current (own) instance
Alternate command device function
The RAID Manager software issues commands to the command device via the UNIX/PC raw I/O
interface. If the command device fails in any way, all RAID Manager commands are terminated
abnormally, and you cannot use any commands. Because the use of alternate I/O path is platform
dependent, restrictions are placed upon it. For example, on HP-UX systems, only devices subject
18 RAID Manager software environment