You can configure vSphere Replication to compress the data that it transfers through the network.
Compressing the replication data that is transferred through the network saves network bandwidth and might help reduce the amount of buffer memory used on the vSphere Replication server. However, compressing and decompressing data requires more CPU resources on both the source site and the server that manages the target datastore.
Data Compression Support
vSphere Replication 6.0 supports end-to-end compression when the source and target ESXi hosts are also version 6.0. The support of data compression for all other use cases depends on the versions of source and target ESXi hosts. The vSphere Replication servers on both the source and target sites must be 6.0.
|Source ESXi host||ESXi Host that Manages the Target Datastore||Data Compression Support|
|Earlier than 6.0||Any supported version||vSphere Replication does not support data compression for the source ESXi host, so the option Enable network compression for VR data is disabled in the Configure Replication wizard.|
|6.0||Earlier than 6.0||The ESXi host on the source site sends compressed data packets to the vSphere Replication server on the target site. The vSphere Replication server searches the target site for ESXi 6.0 hosts that can decompress the data. If no 6.0 hosts are available for the target datastore, the vSphere Replication server uses the resources of the vSphere Replication appliance to decompress the data, and sends the uncompressed data to the ESXi host.|
|6.0||6.0||This is an environment that supports full end-to-end compression. The ESXi host on the source site compresses the data, and the vSphere Replication server on the target site passes the data off to the ESXi host where the host decompresses the data and writes it to disk.|
Data Compression and vSphere vMotion
If data compression is disabled, you can perform vMotion operations on replication source machines between any pair of hosts that support vMotion and vSphere Replication.
When data compression is enabled, if both the source and the target ESXi hosts support data compression, vMotion operations can be performed as usual. However, if the target ESXi host is earlier than 6.0, vSphere Replication prevents vMotion from moving replication source VMs to that host because it does not support data compression. This prevents DRS from performing automated vMotion operations to hosts that do not support compression. Therefore, if you need to move a replication source VM to an ESXi host earlier than 6.0, before you perform the vMotion operation, you must reconfigure the replication to disable data compression.