HP Hitachi Dynamic Link Manager Software - Manual (Page 39)

Intermittent Error Monitoring Actions
During intermittent error monitoring, HDLM manages the history of errors #
that occurred on each path. If an error occurs on a path, HDLM counts the
number of errors that occurred within the time period specified as the error
monitoring interval, immediately before that error occurred. If the number
reaches the specified condition, then an intermittent error will occur on the
path.
For example, if 30 is set for the error monitoring interval and 3 for the
number of times that the error needs to occur, an intermittent error occurs
on the path if an error occurs three times or more within a time period from
30 minutes before the error to the moment the error occurs. The path will be
excluded from automatic failbacks. A path excluded from automatic failback
has an error status until the user executes the HDLM command's online
operation.
#
An error means a path status transition from Online to Offline(E).
When a User Changes the Intermittent Error Information
During intermittent error monitoring, if a user changes any of the values set
for the intermittent error monitoring or path status, the following are
initialized: the history of errors on the paths managed by HDLM, and the
information for the paths that were excluded from automatic failback. The
following table lists the user operations that cause initialization of intermittent
error information and the target paths for initialization.
Table 2-7 User Operations That Cause Initialization of Intermittent Error
Information and the Target Paths for Initialization
User operation that causes initialization of
intermittent error information
Paths for which
intermittent error
information is initialized
Disabling the intermittent error monitoring function (off) All paths
Re-enabling the intermittent error monitoring function
(on)
(No change in the setting values)
Changing the error monitoring interval or the nubmer of
times that the error needs to occur
Changing the path to the blocked state (Offline(C)) The paths for which the
states have been changed
Changing the path to the active state (Online)
Restarting the host All paths
When intermittent error monitoring is enabled, if the intermittent error
information is initialized, monitoring starts again from that moment. To set
the paths that have been excluded from automatic failback to stay excluded,
HDLM Functions
2-21
Hitachi Dynamic Link Manager User Guide for VMware ®