HP XP7 Storage - Manual (Page 34)

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 on page 2-14 ,
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
When Using Other Than the Thunder 9500V Series and Hitachi AMS/WMS Series
All online paths are owner paths. Therefore, for the example in Figure 2-8
Flow of I/O Data When the Load Balancing Function Is Used on page 2-13 ,
the load is balanced among the four paths A, B, C, and D. If one of the paths
were to become unusable, the load would be balanced among the three,
remaining paths.
Notes:
Load balancing is performed for the following storage systems:
¢
Lightning 9900V series
¢
Hitachi USP series
¢
Universal Storage Platform V/VM series
¢
Virtual Storage Platform series
2-14
HDLM Functions
Hitachi Dynamic Link Manager (for Windows®) User Guide