What is the compression algorithm used by vSphere Replication to compress data at the source?
vSphere Replication 6.0 utilizes the FastLZ compression library. This provides a nice balance of speed, minimal
CPU overhead, and compression efficiency. When using vSphere 6.0 and vSphere Replication 6.0 at both the source and target locations, updates are compressed at the source and stay compressed until they are written to storage at the target. In cases where there is a mixed configuration, packets may be decompressed at some point in the replication path. For example, if a vSphere 6.0 host is connecting to a vSphere Replication 5.8
virtual appliance, packets will not be compressed over the network. Another example: vSphere 6.0 replicating to a vSphere Replication 6.0 virtual appliance, which is writing to vSphere 5.5 host storage – packets are compressed from the source to the vSphere Replication 6.0 –irtual appliance, but are decompressed in the appliance before being written to the vSphere 5.5 storage at the target. Performing this decompression in the vSphere Replication virtual appliance will cause higher vCPU utilization in the appliance. As you can imagine,
the most benefit from compression will be realized when running vSphere 6.0 and vSphere Replication 6.0 at both the source and target locations.