HP XP P9500 Storage - Manual (Page 19)

Figure 5 Relationship of the special file to the special LDEV
Acceptance of commands. A command is issued in the LBA area of the special LDEV explained
above. The RD/WR command meeting this requirement should be received especially as a RAID
Manager command. A command is issued in the form of WR or WR-RD. When a command is
issued in the form of RD, it is regarded as an inquiry (equivalent to a SCSI inquiry), and a RAID
Manager recognition character string is returned.
Command competition
The RAID Manager commands are asynchronous commands issued via the SCSI interface. As a
result, if several processes issue these commands to a single LDEV, the storage system cannot take
the proper action. To avoid such a problem, two or more write commands should not be issued
to a single LDEV. The command initiators should not issue two or more write commands to a single
LDEV unless the storage system can receive commands with independent initiator number * LDEV
number simultaneously.
Figure 6 HORCM and command issue process
Command flow
This figure shows the flow of read/write command control for a specified LBA#.
RAID Manager components on the RAID storage system 19