9 working with managers and quorum, Managers overview, Best practice for managers in a management group – HP LeftHand P4000 SAN Solutions User Manual
Page 118: Managers, Functions of managers
9 Working with managers and quorum
When a management group is created using release 10.0, it will be created with the correct
number of managers started. Older management groups upgraded to release 10.0 may require
additional managers or a Failover Manager started before the upgrade to 10.0 can be completed.
See
to see the optimum number of managers required for each configuration.
Managers overview
NOTE:
See the
for definitions of managers, Failover Managers, and virtual managers.
Within a management group, managers are storage systems that govern the activity of all of the
storage systems in the group. All storage systems contain the management software, but you must
designate which storage systems run that software by starting managers on them. These storage
systems then “run” managers, much as a PC runs various services.
Functions of managers
•
Control data replication. They are not directly in the data path and do not participate in I/O.
•
Manage communication between storage systems in the cluster.
•
Resynchronize data when storage systems change states.
•
Coordinate reconfigurations as storage systems are brought up and taken offline.
One storage system has the coordinating manager. You can determine which storage system
is the coordinating manager by selecting the management group, then clicking the Details
tab. The Status field displays the coordinating manager.
Best practice for managers in a management group
When creating a management group, the wizard creates an optimal manager configuration for
the number of storage systems used to create the group. See
for the default
manager configurations.
After you have finished creating the management group, be certain to reconfigure managers as
necessary to optimize your SAN configuration.
Example optimized manager configurations
•
If you have multiple clusters, balance the managers across clusters.
•
If you have a multi-site cluster, ensure that the majority of managers are in the Primary site.
•
If you have a mix of older and newer storage systems, move some of the managers to the
newer storage systems.
NOTE:
Beginning with release 10.0, less-than-optimal manager and quorum configurations
trigger alarms in the CMC, and via email and SNMP traps, if configured. Releases prior to 10.0
indicate manager and quorum issues in the Best Practice Summary on the SAN Status page or in
the Configuration Summary section of the CMC.
IMPORTANT:
The CMC configures the optimal manager configuration when you create a
management group using the Management Groups, Clusters, and Volumes Wizard. If the
management group contains a virtual manager, or if the manager configuration changes from the
recommended number of managers, (for example, by adding or removing storage systems), then
an alarm is triggered. Click Online Event Resolution Help to access the alarm resolution for that
quorum alarm.
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Working with managers and quorum