Setting up Cluster Export Services shared root file system

If you have not set up a shared root file system through the installer, create one for Cluster Export Services (CES).

The CES shared root (cesSharedRoot) is needed for storing CES shared configuration data, for protocol recovery, and for other protocol-specific purposes. It is part of the cluster export configuration and is shared between the protocols. Every CES node requires access to the path configured as shared root.

The mmchconfig command is used to configure this directory as part of setting up a CES cluster.

The cesSharedRoot cannot be changed while any CES nodes are up and running. You need to bring down all CES nodes if you want to modify the shared root configuration.

The cesSharedRoot is monitored by the mmsysmonitor. If the shared root is not available, the CES node list (mmces node list) will show "no-shared-root" and a failover is triggered.

The cesSharedRoot cannot be unmounted when the CES cluster is up and running. You need to bring all CES nodes down if you want to unmount cesSharedRoot (for example, for doing service action like fsck).

To list the current cesSharedRoot, run

mmlsconfig cesSharedRoot

cesSharedRoot /gpfs/gpfs-ces/

The recommendation for CES shared root is a dedicated file system (but this is not enforced). It can also be a part (path) of an existing GPFS™ file system. A dedicated file system can be created with the mmcrfs command. In any case, CES shared root must reside on GPFS and must be available when it is configured through mmchconfig.

If not already done through the installer, it is recommended that you create a file system for the CES. Some protocol services share information through a cluster-wide file system. It is recommended to use a separate file system for this purpose.

Note: The recommended size for CES shared root file system is greater than or equal to 4GB.

To set up CES, change the configuration to use the new file system:

mmchconfig cesSharedRoot=/gpfs/fs0

Note: Once GPFS starts back up, by virtue of the fact that the cesSharedRoot is now defined, then CES can be enabled on the cluster.