HP XP7 Storage - Manual (Page 17)

command devices (see “Alternate command device function” (page 18) ) must be set to avoid data
loss and storage system downtime.
Each command device must be set using the LUN Manager software on Remote Web Console. In
addition, for using a Provisioning command, user authentication is required. Set the security attribute
of the command device with user authentication. For information and instructions on setting a
command device, see the Provisioning Guide for the storage system.
Each command device must also be defined in the HORCM_CMD section of the configuration file
for the RAID Manager instance on the attached host. If an alternate command device is not defined
in the configuration file, the RAID Manager software may not be able to use the device.
The RAID Manager Data Protection Facility uses an enhanced command device that has an attribute
to indicate protection ON or OFF.
NOTE:
•
For Solaris operations, the command device must be labeled.
To enable dual path of the command device, make sure to include all paths to the command device
on a single line in the HORCM_CMD section of the configuration file. The following shows an
example with two controller paths to the command device. Putting the path information on separate
lines may cause parsing issues, and failover may not occur unless the HORCM startup script is
restarted.
HORCM_CMD #dev_name dev_name dev_name /dev/rdsk/c1t66d36s2
/dev/rdsk/c2t66d36s2
Command device guarding
In the customer environment, a command device may be attacked by the maintenance program
of the Solaris Server, after that usable instance will be exhausted, and RAID Manager instance
would not start up on all servers (except attacked server). This may happen due to incorrect operation
of the maintenance personnel for the UNIX Server. In this case, the command device should be
protected against operator error, as long as it can be seen as the device file from the maintenance
personnel.
Thus, the RAID microcode (for the command device) and RAID Manager support this protection in
order to guard from similar access.
Guarding method
Currently, assignment of the instance via the command device is ONE phase. Therefore, if the
command device reads a special allocation area of the instance through the maintenance tool and
so on, then it causes a fault of full space of the instance, because the command device interprets
as assignment of the instance from RAID Manager.
RAID Manager has TWO phases that it reads to acquire usable LBA, and writes with the acquired
LBA in attaching sequence to the command device, so the command device can confirm whether
it was required as the assignment for RAID Manager or not, by detecting and adding two status
bits to the instance assignment table.
RAID Manager components on the RAID storage system 17