I have a VNX5700 replicating vdms and file systems to another 5700.

We have always set up the file system replications allowing them to be created on the target from the file pool by the replication process.

When the FS on the source increases, the target FS increases, etc.

Why do people specify the FS on the target side?

Does this allow you to specify the size of the target fs? Does it require manual extensions when the source fs is extended?

What I would like to do is save space consumed by file systems on the target. For example, I have a 4 TB fs on the source vnx that deduped to 1 TB, the problem is the replication is "wasting" 3 TB just in free space.