Configure SMB Multichannel for performance and redundancy
Beginning in ONTAP 9.4, you can configure SMB Multichannel to provide multiple connections between ONTAP and clients in a single SMB session. Doing so improves throughput and fault tolerance.
You can use SMB Multichannel functionality only when clients negotiate at SMB 3.0 or later versions. SMB 3.0 and later is enabled on the ONTAP SMB server by default.
SMB clients automatically detect and use multiple network connections if a proper configuration is identified on the ONTAP cluster.
The number of simultaneous connections in an SMB session depends on the NICs you have deployed:
1G NICs on client and ONTAP cluster
The client establishes one connection per NIC and binds the session to all connections.
10G and larger capacity NICs on client and ONTAP cluster
The client establishes up to four connections per NIC and binds the session to all connections. The client can establish connections on multiple 10G and larger capacity NICs.
You can also modify the following parameters (advanced privilege):
The maximum number of connections allowed per Multichannel session. The default is 32 connections.
If you want to enable more connections than the default, you must make comparable adjustments to the client configuration, which also has a default of 32 connections.
The maximum number of network interfaces advertised per Multichannel session. The default is 256 network interfaces.
Set the privilege level to advanced:
set -privilege advanced
Enable SMB Multichannel on the SMB server:
vserver cifs options modify -vserver vserver_name -is-multichannel-enabled true
Verify that ONTAP is reporting SMB Multichannel sessions:
vserver cifs session show options
Return to the admin privilege level:
set -privilege admin
The following example displays information about all SMB sessions, showing multiple connections for a single session:
cluster1::> vserver cifs session show Node: node1 Vserver: vs1 Connection Session Open Idle IDs ID Workstation Windows User Files Time ---------- ------- ---------------- ---------------- --------- --------------- 138683, 138684, 138685 1 10.1.1.1 DOMAIN\ 0 4s Administrator
The following example displays detailed information about an SMB session with session-id 1:
cluster1::> vserver cifs session show -session-id 1 -instance Vserver: vs1 Node: node1 Session ID: 1 Connection IDs: 138683,138684,138685 Connection Count: 3 Incoming Data LIF IP Address: 220.127.116.11 Workstation IP Address: 10.1.1.1 Authentication Mechanism: NTLMv1 User Authenticated as: domain-user Windows User: DOMAIN\administrator UNIX User: root Open Shares: 2 Open Files: 5 Open Other: 0 Connected Time: 5s Idle Time: 5s Protocol Version: SMB3 Continuously Available: No Is Session Signed: false NetBIOS Name: -