Dell VNX5800 VNX Series: Introduction to SMB 3.0 Support - Page 17

Transferring data to the client and back results in wasted resources and adds additional overhead. Offload copy is designed to improve efficiency by allowing the Data Mover to do the copy instead of sending data to the host and back again. It is a token-based copy method where a 512-byte token is used to represent up to 256MB of actual data. SPB SPA 4 Data Mover 3 Data Mover 2 123 5 Command Data Token Figure 11 Offload Copy Figure 11 describes the sequence of events for an Offload Copy: 1. The client submits a copy request for a file. 2. The Data Mover builds a token and sends it to the client. 3. The client uses the token to generate the write request. 4. The Data Mover performs the copy. 5. The Data Mover acknowledges the client. The main benefit of Offload Copy is the elimination of reading and writing data across the network. The host CPU usage and network bandwidth required is reduced. EMC VNX Series: Introduction to SMB 3.0 Support 17