Hitachi Dynamic Link Manager Software Users Guide for Linux

among the remaining usable owner paths. When all owner paths cannot be

used, load balancing is performed among the non-owner paths.

For the example in Figure 2-9 Overview of Load Balancing on page 2-16,

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. Thus, for the example in Figure 2-8 Flow of

I/O Data When the Load Balancing Function Is Used on page 2-15, 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

VSP G1000 series

2-16

HDLM Functions

Hitachi Dynamic Link Manager (for Linux®) User Guide