Creating and configuring stable storage for NFS version 4 exports
Stable storage is a file system space that is used to save the state information by the NFS version 4 server. This is very crucial for maintaining NFS version 4 client's state information to facilitate smooth and transparent fallover/fallback/move of the Resource group from one node to another.
Requirements of stable storage:
- The suggested size is 512 MB.
- It is suggested that you have a dedicated file system for the stable storage, but a subdirectory of an existing file system is acceptable.
- The file system and volume group where the Stable Storage resides should be part of the resource group.
- PowerHA® SystemMirror® makes a best-effort attempt to verify that the path specified for stable storage belongs to a file system in the resource group; however, these checks are not able to take symbolic links into account since the file systems might not be mounted locally when the verification occurs. Avoid using symbolic links that can interfere with verification in PowerHA SystemMirror.
- Ensure that the stable storage directory is empty (free of any prior data) prior to adding it to the resource group.
- While stable storage must be stored in file systems managed by the resource group, it should not be stored in an NSF directory that is exported by the resource group.
- Configuration assistant offers an AUTO_SELECT option. If you select this option, PowerHA SystemMirror uses a volume group from the list of volume groups that are part of the given resource group. PowerHA SystemMirror then creates a logical volume and a file system to use as the stable storage location.