Command Device Guarding - Hitachi VSP F1500 User And Reference Manual

(for example, for online maintenance), you can switch to an alternate
command device manually. If no alternate command device is defined or
available, all TrueCopy and ShadowImage commands terminate abnormally,
and the host will not be able to issue commands to the storage system.
Therefore, one or more alternate command devices (see Alternate command
device function on page 2-5) must be set to avoid data loss and storage
system downtime.
Each command device must be set using the LUN Manager software on
Storage Navigator. 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 definition file for the CCI instance on the attached host. If
an alternate command device is not defined in the configuration definition
file, the CCI software might not be able to use the device.
The CCI 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 definition file. The following shows an example with two
controller paths to the command device. Putting the path information on
separate lines might cause parsing issues, and failover might 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 might be attacked by the
maintenance program of the Solaris Server, after that usable instance will be
exhausted, and CCI instance would not start up on all servers (except
attacked server). This might 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 CCI 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
2-3
CCI software environment
Command Control Interface User and Reference Guide