VERITAS Volume Manager 3.5 Administrator's Guide (September 2004)

Administering Dynamic Multipathing (DMP)
Administering DMP Using vxdmpadm
Chapter 3 127
# vxdmpadm start restore policy=check_all
[interval=seconds]
• check_alternate
The restore daemon checks that at least one alternate path is
healthy. It generates a notification if this condition is not met. This
policy avoids inquiry commands on all healthy paths, and is less
costly than check_all in cases where a large number of paths are
available. This policy is the same as check_all if there are only two
paths per DMP node. The command to start the restore daemon with
this policy is:
# vxdmpadm start restore policy=check_alternate
[interval=seconds]
• check_disabled
This is the default policy. The restore daemon checks the condition of
paths that were previously disabled due to hardware failures, and
revives them if they are back online. The command to start the
restore daemon with this policy is:
# vxdmpadm start restore policy=check_disabled
[interval=seconds]
• check_periodic
The restore daemon performs check_all once in a given number of
cycles, and check_disabled in the remainder of the cycles. This policy
may lead to periodic slowing down (due to check_all) if there are a
large number of paths available. The command to start the restore
daemon with this policy is:
# vxdmpadm start restore policy=check_periodic
interval=seconds [period=number]
The interval attribute must be specified for this policy. The default
number of cycles between running the check_all policy is 10.
The interval attribute specifies how often the restore daemon examines
the paths. For example, after stopping the restore daemon, the polling
interval can be set to 400 seconds using the following command:
# vxdmpadm start restore interval=400
The default interval is 300 seconds. Decreasing this interval can
adversely affect system performance.