HP XP Racks - Manual (Page 239)

activate path health checking so that you can detect errors in paths
where I/Os operations do not occur.
When you specify on, specify the checking interval of path health
checking by specifying the parameter immediately following on. If you do
not specify a checking interval, path health checking is executed in the
following interval:
¢
When the checking interval has not been specified before:
Every 30 minutes (default setting)
¢
When the checking interval has been specified before:
The previously specified interval
The explanation for the following sub-parameter describes how to specify
the checking interval.
-intvl checking-interval
Specify the checking interval between path health checks. Specify a
value from 1 to 1440 minutes depending on the user environment.
When you change the checking interval, the new setting takes effect
immediately. When the checking interval is shortened and the
checking interval after the change (from the end of the previous path
health check) has already elapsed, the path health check will start
over.
The path health check interval setting remains stored in the system
even if you disable the function by changing the path health checking
to off. Therefore, when you re-enable path health checking and do
not change the interval, the path health interval stored in the system
is used.
-afb {on [-intvl checking-interval]|off}
Enables or disables automatic failback.
on: Enabled
off: Disabled
Enabling automatic failbacks might automatically place online 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.
Command Reference
6-23
Hitachi Dynamic Link Manager (for AIX) User Guide