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This article describes the features of the Server Message Block (SMB) 3.0 protocol.
Original KB number: 2709568
Windows Server 2012 introduced new SMB file server features. To take advantage of these features, the SMB client and SMB server must support SMB 3.0.
The SMB 2.x protocol was introduced in Windows Server 2008 and Windows Vista.
The SMB 3.0 protocol was introduced in Windows Server 2012 and Windows 8.
Both the SMB client and SMB server must support SMB 3.0 to take advantage of the SMB Transparent Failover functionality.
SMB 1.0- and SMB 2.x-capable clients will be able to connect to, and access, shares that are configured to use the Continuously Available property. However, SMB 1.0 and SMB 2.x clients won't benefit from the SMB Transparent Failover feature. If the currently accessed cluster node becomes unavailable, or if the administrator makes administrative changes to the clustered file server, the SMB 1.0 or SMB 2.x client will lose the active SMB session and any open handles to the clustered file server. The user or application on the SMB client computer must take corrective action to reestablish connectivity to the clustered file share.
Note
SMB Transparent Failover is incompatible with volumes enabled for short file name (8.3 file name) support or with compressed files (such as NTFS-compressed files).
Both the SMB client and SMB server must support SMB 3.0 to take advantage of the SMB Scale Out feature.
SMB 1.0 clients don't contain the required client functionality to access SMB scale-out file shares and will receive an Access Denied error message when they try to connect to a scale-out file share.
SMB scale-out file shares are always configured so that the Continuously Available property is set. SMB 2.x clients will be able to connect to SMB scale-out file shares but won't benefit from the SMB Transparent Failover functionality.
Both the SMB client and SMB server must support SMB 3.0 to take advantage of the SMB Multichannel functionality. SMB 1.0 and SMB 2.x clients will use a single SMB connection.
SMB Direct is available in Windows Server 2012, Windows 10 (Enterprise, Education, and Pro for Workstations editions), and later versions. SMB Direct Functionality requires that the SMB client and SMB server support SMB 3.0.
Both the SMB client and SMB server must support SMB 3.0 to take advantage of the SMB Encryption functionality.
Both the SMB client and SMB server must support SMB 3.0 to take advantage of the Volume Shadow Copy Service (VSS) for SMB file shares functionality.
Both the SMB client and SMB server must support SMB 3.0 to take advantage of the SMB Directory Leasing functionality.
SMB PowerShell management cmdlets were introduced in Windows Server 2012 and in Windows 8. Older SMB clients and SMB servers will have to continue using down-level tools for management (for example, net.exe) and APIs (for example, Win32 APIs).
For more information about the common errors you may experience with SMB 3.0, see Error messages on SMB connections.
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