Monitoring Intermittent Errors (Functionality When Automatic Failback Is Used); Checking Intermittent Errors - Hitachi XP P9500 User Manual

hardware is then re-installed, HDLM will automatically place the path back
online. However, this is the case only when there is no other cause or
reason for the path being placed offline. In this case, because HDLM will
automatically place the path back online without using the automatic
failback function, you do not need to manually place the path online.
When you use the LU dynamic deletion function, the Online(E) path will be
deleted. Therefore, that path is not displayed in the Path Management
window. Also, the view operation does not display the Online(E) path.
Note:
If there is a path failure immediately after a path is taken offline by using
either the an HDLM command or the HDLM GUI, the status might change
from Offline(C) to Offline(E). If an offline operation was just
performed, wait about 2 minutes, check the path status by using an
HDLM command or the HDLM GUI, and then make sure that the status
has changed to Offline(C). If it is still Offline(E), retry the offline
operation.
Monitoring Intermittent Errors (Functionality When
Automatic Failback Is Used)
An intermittent error refers to an error that occurs irregularly because of
something like a loose cable. In such a case, I/O performance might decrease
while an automatic failback is being performed to repair an intermittent error.
This is because the automatic failback operation is being performed
repeatedly (because the intermittent error keeps occurring). To prevent this
from happening, HDLM can automatically remove the path where an
intermittent error is occurring from the paths that are subject to automatic
failbacks. This process is called intermittent error monitoring.
We recommend that you use intermittent error monitoring along with the
automatic failback function.
A path in which an error occurs a specified number of times within a specified
interval is determined to have an intermittent error. The path where an
intermittent error occurs has an error status until the user chooses to place
the path back online. Failbacks are not performed for such paths. This status
is referred to as the not subject to auto failback status.

Checking Intermittent Errors

You can check the paths in which intermittent errors have occurred by
viewing the execution results of the HDLM command's view operation or the
HDLM GUI Path List view.
For details on the view operation, see
6-29. For details on how to use the Path List view of the HDLM GUI and
window components, see the HDLM GUI Help.
2-24
HDLM Functions
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