Dell VNX5800 VNX Series: Introduction to SMB 3.0 Support - Page 7

SMB 3.0 on VNX Beginning with VNX File Operating Environment (OE) version 7.1.65, the SMB 3.0 protocol is now enabled by default on VNX. To check if SMB 3.0 is enabled on your DM, use the server_cifs command to check the Max Protocol as shown in Figure 1. Figure 1 Check SMB 3.0 If SMB 3.0 is not enabled on your DM, you can enable it using the server_cifs command as shown in Figure 2. Figure 2 Enable SMB 3.0 Continuous Availability (CA) In a client or CIFS server failure, the Continuous Availability (CA) feature allows Windows-based clients to persistently access CIFS shares without the loss of the session state. You can leverage this feature when planning with storage availability in mind for business-critical applications such as Microsoft SQL Server, IIS, and Hyper-V. Server failover For a CIFS server to recover client content in a Data Mover failover, persistent handles are introduced in SMB 3.0. When CA is enabled on a share, persistent handles enable a CIFS server to save specific metadata associated to an open file handle on disk. When a Data Mover failover occurs, the new primary Data Mover reads the metadata from disk before starting the CIFS service. The client will re-establish its session to the Data Mover and attempt to re-open its files and the Data Mover will return the persistent handle to the client. The end result is no impact to the application accessing the open files, if the failover time does not exceed the application timeout. It is important to note that whether CA works in a Data Mover failover or failback situation is dependent on the timeout of the application. As long as the Data Mover failover or failback period does not exceed the timeout of the application, the application can remain online. EMC VNX Series: Introduction to SMB 3.0 Support 7