Detecting Errors By Using Path Health Checking; Error Management - Hitachi XP P9500 User Manual

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
Operating Environment) on page

Error Management

For troubleshooting purposes, HDLM collects information and stores it into log
files. The error information to be collected can be filtered out by error level,
and then stored into the log files.
Figure 2-13 Flow of Data When Collecting Error Information on page 2-28
shows the data flow when collecting error information on a host where HDLM
is running.
HDLM Functions
Hitachi Dynamic Link Manager User Guide (for Solaris(R))
set (Sets Up the
6-16.
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