Novell LINUX ENTERPRISE SERVER 11 - STORAGE ADMINISTRATION GUIDE 2-23-2010 Administration Manual page 64

Multipath Attribute
path_selector
pg_timeout
64 SLES 11: Storage Administration Guide
Description
Specifies the path-selector
algorithm to use for load
balancing.
Specifies path group timeout
handling.
Values
round-robin 0: (Default) The load-balancing
algorithm used to balance traffic across all active
paths in a priority group.
Beginning in SUSE Linux Enterprise Server 11,
the following additional I/O balancing options are
available:
least-pending: Provides a least-pending-I/O
dynamic load balancing policy for bio based
device mapper multipath. This load balancing
policy considers the number of unserviced
requests pending on a path and selects the path
with least count of pending service requests.
This policy is especially useful when the SAN
environment has heterogeneous components.
For example, when there is one 8GB HBA and
one 2GB HBA connected to the same server, the
8GB HBA could be utilized better with this
algorithm.
length-load-balancing: A dynamic load
balancer that balances the number of in-flight I/O
on paths similar to the least-pending option.
service-time: A service-time oriented load
balancer that balances I/O on paths according to
the latency.
NONE (internal default)