HP Hitachi Dynamic Link Manager Software - Manual (Page 46)

2. HDLM Functions
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have different owner controllers, different LUs might also have different owner paths.
A non-owner path is a path that passes through a CHA other than the owner controller.
This type of CHA is also known as a non-owner controller. An owner path is usually
used in preference to a non-owner path. In order to prevent system performance from
slowing down, HDLM does not perform load balancing between owner paths and
non-owner paths. If failures occur across some of the owner paths, load balancing will
be performed among the remaining, usable owner paths. It is only when absolutely no
owner paths are available, that load balancing is then performed among the non-owner
paths.
For the example in Figure 2-9: Overview of Load Balancing, suppose that in the
owner controller of LU0 is CHA0. When the LU is accessed, the load is balanced
between the two paths A and B, which are both owner paths. When one of the paths
(A) cannot be used, then the LU is accessed from the only other owner path (B). When
both of the owner paths (A and B) cannot be used, the load is then balanced between
two other, non-owner paths (C and D).
Figure 2-9: Overview of Load Balancing