Although Unity has been in the market for more than a year, until recently, I got a chance to configure a pair of Unity with file replication. If you were a VNX/Celerra user, there are 3 points you need to be aware to configure the file system replication on Unity.
- File System replication is bundled with NAS server replication
When replicating existing File Systems or VMware NFS Datastores with asynchronous replication, you must first configure replication for the NAS Server it is mounted on. It is not supported to replicate file system to a different Unity NAS server at the remote site.
When deleting a NAS server, the related file system must be deleted as well.
- Target file system cannot be accessed until failover.
When a remote file system replication session is setup, it is noted that the remote site target file system cannot be accessed until the failover took place. Comparing with VNX file system replication, the target file system could be mounted as read-only for backup/testing purpose, but this is not supported in Unity at this stage.
- Backup/Test Interface
There is one special interface “Backup and DR Test” could be configured on NAS server at both source and target NAS servers. However, this interface only support NFS by Unity OE version 4.2. Also, for NFS, you can only use this interface to access the mounted NFS file system snapshot.
A quick summary, Unity bring a simple wizard to configure the file system replication and make the replication easier to control and the DR procedure is even easier. However, some functions is not supported as stated in the post and would expect the be supported in the future release.