HP XP7 Storage User Manual

Page 214

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

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:

error-monitoring-interval >= checking-interval-for-automatic-

failback x number-of-times-error-is-to-occur-during-

intermittent-error-monitoring

If this condition is not satisfied, the KAPL01080-W message will be

output and an error will occur. If this happens, change any of the

following settings: the checking interval for automatic failbacks, the

intermittent error-monitoring interval, or the number of times that the

error is to occur.

6-22

Command Reference

Hitachi Dynamic Link Manager (for Windows®) User Guide

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