HP Hitachi Dynamic Link Manager Software - Manual (Page 44)

When the Lightning 9900 series, Lightning 9900V series, Hitachi USP series,
Universal Storage Platform V/VM series, Virtual Storage Platform series,
Hitachi AMS2000 series
# , Hitachi SMS series # , HUS100 series # , or HUS VM is
being used, all the paths are owner paths. This means that all the paths that
are accessing the same LU are possible switching destinations. For example,
in Figure 2-10 Path Switching on page 2-20 , the LU is accessed using only
the one path (A). However, after that path is placed offline, the switching
destination can come from any of the other three paths (B, C, or D).
#
This storage system applies when the dynamic I/O path control function is
disabled.
Figure 2-10 Path Switching
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
2-20
HDLM Functions
Hitachi Dynamic Link Manager User Guide for Linux ®