tree 962e8f354dfe3df2021476412be8d1bcec8a03d0
parent fd5e033908b7b743b5650790f196761dd930f988
author Kiyoshi Ueda <k-ueda@ct.jp.nec.com> 1245661948 +0100
committer Alasdair G Kergon <agk@redhat.com> 1245661948 +0100

dm mpath: add service time load balancer

This patch adds a service time oriented dynamic load balancer,
dm-service-time, which selects the path with the shortest estimated
service time for the incoming I/O.
The service time is estimated by dividing the in-flight I/O size
by a performance value of each path.

The performance value can be given as a table argument at the table
loading time.  If no performance value is given, all paths are
considered equal.

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>