HP Hitachi Dynamic Link Manager Software User Manual

Page 255

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6. Command Reference

231

on

: Enabled

off

: Disabled

Enabling automatic failbacks might automatically place paths online that were

intentionally placed offline (for example, paths placed offline for maintenance

work).
If you want to prevent such paths from automatically being placed online, disable

this function. When intermittent errors occur in paths or storage systems, statuses

of paths alternates between the online and offline status frequently, thus

decreasing I/O performance.
Automatic failbacks are performed on the following types of paths:

Paths where an error occurred and for which the KAPL08022-E message

was displayed

Path where an error occurred during the startup of the HDLM manager.

To prevent intermittent errors from deteriorating I/O performance, we

recommend that you also enable intermittent error monitoring when the automatic

failback function is enabled. Intermittent error monitoring is specifiable only

when automatic failbacks are enabled.
See Table 6-5: Relationship Between the Setting for the Automatic Failback

Function and Intermittent Error Monitoring and the Executable Operations for

the relationship between automatic failbacks and intermittent error monitoring.
When you specify

on

, specify the checking interval by specifying the parameter

immediately following

on

. If you do not specify a checking interval, path statuses

will be checked in the following way:

When the checking interval has not been specified before:

Every minute (default setting)

When the checking interval has been specified before:

The previously used interval

The explanation for the following sub-parameter describes how to specify the

interval between path status checks.

-intvl

checking-interval

Specify the interval between path status checks. Specify a value from 1 to

1440 minutes. Specify an interval appropriate for your operating

environment.
If intermittent error monitoring is

on

and the number of times that the error

is to occur is set to a value of 2 or more, the following condition must be

satisfied:

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