HP Hitachi Dynamic Link Manager Software - Manual (Page 58)

2. HDLM Functions
36
2.10 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, and Hitachi AMS/WMS series storage system). Because of
this, for the standby host or for a host connected to non-owner paths, we recommend
that you use path health checking to detect errors. This enables the system to use the
most up-to-date path-status information when selecting the next path to use.
You can configure path health checking by executing the
dlnkmgr
command's
set
operation. For details on the
set
operation, see 6.6 set (Sets Up the Operating
Environment).