HP Hitachi Dynamic Link Manager Software Licenses - Manual (Page 39)

For example, in Figure 2-8 Path Switching on page 2-17 , the owner
controller of LU is CHA0, and access to the LU is made only via the physical
path (A). After the access path is placed offline, the first candidate for the
switching destination is the physical path (B) and the second candidate is the
physical path (C or D).
When the Lightning 9900V Series, Hitachi USP Series, Universal Storage
Platform V/VM Series, Virtual Storage Platform Series, VSP G1000 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 2-8 Path Switching on page 2-17 , the LU is accessed
using only the one physical path (A). However, after that path is placed
offline, the switching destination can come from any of the other three
physical paths (B, C, or D).
#
This storage system applies when the dynamic I/O path control function is
disabled.
Paths are switched in units of physical paths. Therefore, if an error occurs in a
path, HDLM switches all the other paths that run through the same physical
path.
Figure 2-8 Path Switching
HDLM Functions
2-17
Hitachi Dynamic Link Manager (for Solaris) User Guide