Setting up Cluster Export Services shared root file system

If a shared root file system through the installer is not set up, you must 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 of the CES nodes are up and running. Follow these steps to modify the shared root configuration:

Run the following command to suspend all CES nodes:
```
mmces suspend --stop -a
```
Run the following command to shut down all the CES nodes:
```
mmshutdown -a
```
Create cesSharedRoot by using the following command:
```
mmchconfig cesSharedRoot=/gpfs/fs0
```
Run the following command to start GPFS on all the CES nodes:
```
mmstartup -a
```
Run the following command to activate CES:
```
mmces resume --start -a
```

The cesSharedRoot is monitored by the system health daemon. If the shared root is not available, the CES node list command, mmces node list displays 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 it 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 the mmchconfig command.

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 4 GB. It is recommended to use the following settings for the CES shared root file system if it is used for CES shared root only:

Block size: 256 KB
Starting inode-limit: 5000

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

mmchconfig cesSharedRoot=/gpfs/fs0

Note:

When the GPFS starts back up, as the cesSharedRoot is now defined, the CES can be enabled on the cluster.
If file audit logging is already enabled for the file system that you defined for cesSharedRoot, you need to first disable and then enable it again for that file system.
```
mmaudit Device disable
```
```
mmaudit Device enable
```