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Fail over to a standby Group Manager
When you need to have a standby Group Manager take over control of group management, log in to the standby system
and run this “take control” command:
ap2>icapmanage -Q
This command establishes ap2 as the active Group Manager for all managed groups and group members, limited only
to the extent that ap2 can contact the member systems and the previously active Group Manager. That is, the new
Group Manager (ap2) attempts to contact the previously active Group Manager (ap1) to put it in standby status. In the
case of planned downtime, this should be no problem as long as the “take control” command is issued before taking an
active Group Manager off line. In the case of a sudden failure of an active Group Manager, the new active Group Manager
most likely cannot contact the previously active Group Manager. This has some implications for failback, as discussed in
the “Split groups and failback” subsection.
The new active Group Manager also attempts to contact all group members, informing them that this system is the
active Group Manager. Standard group operations can then be continued on the new active Group Manager for all the
members that are contactable. As long as the new active Group Manager can contact one host on a group member, the
new active Group Manager becomes the active manager for that member.
Fail back from a standby Group Manager
In the case, where a standby Group Manager took control as part of planned maintenance, control is restored to the
formerly active Group Manager through the following two commands:
ap1> icapmanage -Q
The icapmanage -Q command on ap1 restores ap1 as the active Group Manager and ap2 as the standby Group Manager,
as long as both Group Managers are accessible and able to exchange information.
Inaccessible members during Group Manager status changes
If a newly active Group Manager cannot contact a group member during a failover or failback transition, that group
member will continue to believe itself managed by its current manager (the previously active Group Manager). This may
result in the member not being able to loan or borrow usage rights, or it may result in a split group if the previously
active Group Manager also could not be contacted at the time the standby Group Manager took control of the group.
For more details, see the “Split groups and failback” subsection.
In the case where the previously active Group Manager successfully manages the transition to standby status, but a
member was inaccessible during this failover or failback transition, that member will be unable to loan or borrow usage
rights in the group. To recover from this situation, you reestablish communication between the member and the newly
active Group Manager by issuing the icapmanage -Q command on the newly active Group Manager once the member is
back online.