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1 displaying path information, 2 when a path error is detected – HP Hitachi Dynamic Link Manager Software User Manual

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4. HDLM Operation

178

4.1 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.

4.1.1 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.

4.1.2 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 2.9 Detecting errors by using path health checking.
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