HiCommand Dynamic Link Manager (HDLM) for Windows Systems User's Guide (HIT5201-96001, January 2008)

HiCommand
®
Dynamic Link Manager (HDLM) for Windows
®
Systems User’s Guide 25
Table 2.5 Algorithms for Load Balancing
Algorithm For Sequential Access For Random Access
Round robin After an I/O operation is issued to a path once or a certain number of times, the path is switched to the
next path.
The storage system cache might not be fully usable.
When multiple applications that request sequential access are run concurrently, we recommend that you
use the round robin algorithm to distribute I/Os across multiple paths.
1
Extended round
robin
After an I/O operation is issued to a path a certain
number of times in succession, the path is switched to
the next path. If sequential access is switched to
random access before an I/O operation is issued to a
path a certain number of times, the path is switched to
the next path when sequential access is switched to
random access.
The storage system cache can be used.
When you execute only a single application that
requests sequential access (such as a batch job
running at night) we recommend that you use the
extended round robin algorithm.
1
After an I/O operation is issued to a path once
or a certain number of times, the path is
switched to the next path.
1
The recommended algorithm depends on the type of application, and the operations policy.