Automatic Failbacks - Hitachi XP P9500 User Manual

Automatic Failbacks

When a path recovers from an error, HDLM can automatically place the
recovered path back online. This function is called the automatic failback
function. In order to use the automatic failback function, HDLM must already
be monitoring error recovery on a regular basis.
When using the Thunder 9500V series, or Hitachi AMS/WMS series, HDLM will
select the next path to be used first from among the online owner paths, and
then from the online non-owner paths. As a result, if an owner path recovers
from an error, and then HDLM automatically places the recovered path online
while a non-owner path is in use, the path will be automatically switched over
from the non-owner path to the owner path that just recovered from the
error.
When the Lightning 9900 series, Lightning 9900V series, Hitachi USP,
Universal Storage Platform V/VM, Virtual Storage Platform, Hitachi AMS2000
series, or Hitachi SMS is being used, all the paths are owner paths. As a
result, if the path that was previously used recovers from an error, and then
HDLM automatically places the recovered path online, the path that is
currently being used will continue to be used (as opposed to switching over to
the path that was just recovered).
2-20
Figure 2-10 Path Switching
HDLM Functions
Hitachi Dynamic Link Manager User Guide (for Linux(R))