HP Hitachi Dynamic Link Manager Software Licenses - Manual (Page 45)

When you are using intermittent error monitoring, the path in which the
intermittent error occurred is not automatically placed online even when the
path recovers from the error. In such a case, place the path online manually.
Note
If there is a path failure immediately after a path is placed offline by using
the dlnkmgr command, Offline(C) might change to Offline(E). If an offline
operation was performed, wait for a fixed period of time (about 2
minute), check the path status by using the dlnkmgr command, and
make sure that the status has changed to Offline(C). If it is Offline(E),
retry the offline operation.
Intermittent Error Monitoring (Functionality When
Automatic Failback Is Used)
An intermittent error means an error that occurs irregularly because of, for
example, a loose cable connection. 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. Automatic 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.
For details on the view operation, see view (Displays Information) on page
6-34 .
Setting Up Intermittent Error Monitoring
When you use the intermittent error function, you can enable or disable the
function. If you enable the function, specify the monitoring conditions: the
error monitoring interval, and the number of times that the error is to occur.
If an error occurs in a path the specified number of times within the specified
error monitoring interval, the system determines that the path has an
intermittent error. For example, if you specify 30 for the error monitoring
interval and 3 for the number of times that the error is to occur, the path is
HDLM Functions
2-23
Hitachi Dynamic Link Manager (for Solaris) User Guide