HP XP7 Storage - Manual (Page 215)

Operational notes and restrictions for RAID Manager operations
For maintenance of volumes used by RAID Manager and the HP features it supports, if a volume
failure occurs, it is important to find the failure in the paired volumes, recover the volumes, and
continue operation on the original system. When a RAID Manager (HORCM) or HP feature failure
is detected, please collect the data in the error log file and trace data (all files in HORCM_LOG
directory), and report the failure to your HP representative.
Notes and restrictions Items
When the server starts up, the secondary volume may be updated by the primary volume's
server. The secondary volume must not be mounted automatically in the startup sequence. Startup/shutdown
restrictions
If the secondary volume is used by the LVM, the volume group of the LVM must be
deactivated. The secondary volume must be mounted in the split state or in the simplex
mode.
When the server starts up, the secondary volume can be activated without confirming,
when can be guaranteed that the secondary volume has been PSUS (R/W enable) or in
the SMPL state by server shutdown sequence.
Continuous Access Synchronous commands cannot execute hot standby operations between
the primary and secondary volumes. Use the takeover command intended for the HA Hot standby operations
configuration to execute the hot standby operation. In hot standby operation, two servers
are used, and the active (primary) and standby (secondary) server programs are run
alternately in each server in case of a failure in one server. Follow these precautions:
• Operation across volumes. Since each Continuous Access Synchronous command causes
the server software to handle the volume by volume, a single volume should not be
partitioned to prevent it from being used by some servers.
•
Using LVM and Continuous Access Synchronous together. When constructing the LVM
on the paired volume in the mutual hot standby configuration, the LVM logical volumes
must be constructed in units of volume to prevent the volumes from being mounted by
the LVM.
When the LVM mirror and Continuous Access Synchronous volumes are used together, the
LVM mirror handles write errors and changes the volumes. Thus, the fence level of the
volumes used by the LVM mirror must be set to data. Coexistence of LVM mirror
and Continuous Access
Synchronous
When constructing paired volume in a single host, it is necessary to activate two or more
RAID Manager instances. To activate two or more RAID Manager instances, instance Using paired volume in a
single host
numbers must be assigned using the environment variable HORCMINST. The HORCM and
Continuous Access Synchronous/Business Copy commands must possess this environment
variable.
A configuration definition file and a log directory is set for each instance. For sharing
command devices over 17 instances, use SCSI path among the storage system ports to
share the command devices.
When paired volume is used for the disk shared by the hosts in hot standby configuration
using HA software, use the primary volume as the shared disk and describe the Sharing volumes in a hot
standby configuration
corresponding hosts using the paired volume in the configuration definition file as shown
below. In the HA configuration, if a Continuous Access Synchronous command issued by
host C fails in host B (because host B has gone down and/or IO_ERROR of the command
device), host A is connected and the command execution is retried.
Operational notes and restrictions for RAID Manager operations 215