Veritas Volume Manager 5.0.1 Administrator's Guide, HP-UX 11i v3, First Edition, November 2009

Table 3-2
Recovery options for I/O throttling
DescriptionPossible settingsRecovery option
I/O throttling is not used.Nonerecoveryoption=nothrottle
DMP throttles the path if the
specified number of queued
I/O requests is exceeded.
Queuedepth (queuedepth)recoveryoption=throttle
DMP throttles the path if an
I/O request does not return
within the specified time in
seconds.
Timebound (iotimeout)recoveryoption=throttle
Configuring DMP path restoration policies
DMP maintains a kernel thread that re-examines the condition of paths at a
specified interval. The type of analysis that is performed on the paths depends
on the checking policy that is configured.
Note: The DMP path restoration thread does not change the disabled state of the
path through a controller that you have disabled using vxdmpadm disable.
When configuring DMP path restoration policies, you must stop the path
restoration thread, and then restart it with new attributes.
See “Stopping the DMP path restoration thread” on page 191.
Use the vxdmpadm start restore command to configure one of the following
restore policies. The policy will remain in effect until the restore thread is stopped
or the values are changed using vxdmpadm settune command.
■ check_all
The path restoration thread analyzes all paths in the system and revives the
paths that are back online, as well as disabling the paths that are inaccessible.
The command to configure this policy is:
# vxdmpadm start restore [interval=seconds] policy=check_all
■ check_alternate
The path restoration thread 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
189Administering Dynamic Multipathing
Administering DMP using vxdmpadm