HP Hitachi Dynamic Link Manager Software Licenses - Manual (Page 50)

User operation
Number of
errors and time
passed since
error
monitoring
started
Information
about paths
not subject to
automatic
failback
monitoring is being
performed
If a path has
been removed
from the paths
subject to
automatic
monitoring, that
path is no
longer
monitored.
Restarting the HDLM manager Reset #3 Inherited
Restarting the host Reset Reset
#1
When you disable the intermittent error monitoring function, information
about paths not subject to automatic failback will be reset. If you do not
want to reset the information about paths not subject to automatic
failback when you turn the intermittent error monitoring function off,
change the target paths to Offline(C).
#2
The number of errors and the time since monitoring started is reset to 0,
and then monitoring restarts in accordance with the changed monitoring
conditions.
#3
The number of errors and the time since monitoring started is reset to 0,
and then monitoring restarts at the time the HDLM manager starts.
Detecting Errors by Using Path Health Checking
HDLM can check the status of paths to which I/Os are not issued, at regular
intervals, and detect errors. This function is called path health checking.
Without path health checking, an error is not detected unless I/O is issued
because the system only checks the path status when I/O is issued. With
path health checking, however, the system checks the status of online paths
at regular intervals regardless of whether I/O is issued. If an error is detected
in a path, the path health checking function switches the status of that path
to Offline(E) or Online(E). You can use the dlnkmgr command's view
operation to check the path error.
For example, in a normal state, I/O is not issued on the paths of the standby
host in the cluster configuration or on the non-owner paths (that is, some of
the paths that access the Thunder 9500V Series, or Hitachi AMS/WMS series
storage system). Because of this, for the standby host or for a host
2-28
HDLM Functions
Hitachi Dynamic Link Manager (for Solaris) User Guide