HP XP7 Storage - Manual (Page 16)

2 RAID Manager software environment
This chapter describes the RAID Manager software environment.
Overview of the RAID Manager software environment
The RAID Manager software environment includes components on the HP RAID storage systems
and the RAID Manager software on the host servers and/or on the Remote Web Console computer.
The RAID Manager components on the storage systems include the user data volumes and RAID
Manager command devices.
Each RAID Manager instance on a host server includes:
•
RAID Manager application files, referred to as HORC Manager (HORCM):
Log and trace files ◦
◦ A command server
◦ Error monitoring and event reporting files
◦ A configuration management feature
•
Configuration definition file (user-defined)
•
User execution environments for the HP features, including the commands, a command log,
and a monitoring function.
The RAID Manager commands also have interface considerations (see “RAID Manager and the
SCSI command interface” (page 19) ).
RAID Manager components on the RAID storage system
Command device
RAID Manager commands are issued by the RAID Manager software to the RAID storage system
command device. The command device is a user-selected, dedicated logical volume on the storage
system that functions as the interface to the RAID Manager software on the host. The command
device is dedicated to RAID Manager communications and cannot be used by any other
applications. The command device accepts RAID Manager read and write commands that are
issued by the storage system. The command device also returns read requests to the host. The
volume designated as the command device is used only by the storage system and is blocked from
the user. The command device uses 16 MB, and the remaining volume space is reserved for RAID
Manager and its utilities. The command device can be any OPEN-x device (for example, OPEN-V)
that is accessible to the host. A LUN Expansion volume cannot be used as a command device. A
Virtual LVI/Virtual LUN volume as small as 36 MB (for example, OPEN-3-CVS) can be used as a
command device.
WARNING! Make sure the volume to be selected as the command device does not contain any
user data. The command device will be inaccessible to the host.
The RAID Manager software on the host issues read and write commands to the command device.
When RAID Manager receives an error notification in reply to a read or write request to the RAID
storage system, the RAID Manager software switches to an alternate command device, if one is
defined. If a command device is blocked (for example, for online maintenance), you can switch
to an alternate command device manually. If no alternate command device is defined or available,
all Continuous Access Synchronous and Business Copy commands terminate abnormally, and the
host will not be able to issue commands to the storage system. Therefore, one or more alternate
16 RAID Manager software environment