HP XP P9500 Hitachi Dynamic Link Manager Software User Guide for VMWare (HIT52 - Page 27

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 2-7 Overview of Load Balancing on page 2-9, 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, nonowner paths (C and D). Figure 2-7 Overview of Load Balancing When Using the Universal Storage Platform V/VM, Virtual Storage Platform, Hitachi AMS2000 Series, or Hitachi SMS All online paths are owner paths. Therefore, for the example in Figure 2-6 Flow of I/O Data When the Load Balancing Function Is Used on page 2-8, 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. Load Balancing Algorithms The load balancing function uses VMware vSphere PSPs. Table 2-4 Load Balancing Algorithms on page 2-10 lists the load balancing algorithms that can be used by HDLM. HDLM Functions 2-9 Hitachi Dynamic Link Manager User Guide (for VMware(R))