HP XP Racks - Manual (Page 168)

Notes on Using HDLM
This section provides notes on using HDLM and using the environment in
which HDLM is installed. Make sure that you read this section.
Displaying Path Information
The AutoPATH_ID that is displayed during the HDLM dlnkmgr command's
view operation differs depending on the order in which paths are detected
when the host starts. For this reason, you should always use the path name
to specify a path.
When a Path Error Is Detected
When a path error is detected by HDLM, you must immediately resolve the
error and restore the path.
A check for path errors is performed whenever an I/O is issued. If there are
any paths through which I/O is not normally issued, such as a non-owner
path, you should enable path health checking in order to detect errors even
when there is no I/O. For details about path health checking, see Detecting
errors by using path health checking on page 2-28 .
When a path is in an error state and the interval specified for a path health
check or a failover has been reached and you execute any of the following,
the response time of the processing might slow down while the path health
check or failover is being executed:
• HDLM command
• HDLM utility
• OS commands for operating volume groups
• mount/umount command
• cfgmgr command
• mkdev command
• rmdev command
• chdev command
When a path is in an error state, if you perform the online operation of the
HDLM command with the -s parameter, it might take a long time for the
command processing to finish.
When a path is in an error state and you want to place all paths or several
paths online at the same time, we recommend that you execute the
command without specifying the -s parameter. If you do this and a path
cannot be placed online, a message confirming that you want to continue the
processing is displayed. If you enter n in response to this message, you can
suspend the command.
4-2
HDLM Operation
Hitachi Dynamic Link Manager User Guide for AIX®