Key NetApp settings to keep in mind when tuning CIFS/SMB performance.
• Use SMB 2.0 over SMB 1.0 wherever possible because SMB 2.0 provides better performance and more security than SMB 1.0.
• TCP Window Size: Set the value to 64K or more if SMB 2.0 is the protocol used.
options cifs.tcp_window_size 64240
Setting TCP window size to 2MB gives very good performance when combined with Windows 7 clients.
• Max outstanding requests per session (Max Mpx): Keep the Max mpx more than the 50 (the default).
This setting improves performance for parallel reads and writes. The values that can be set are 126, 253, or 1124.
options cifs.max_mpx <value>
• Negotiated Buffer Size: This setting controls the maximum negotiated read/write buffer size that can be used. The default is 32k and the size can also be set to 64k.
options cifs.neg_buf_size <value>
Source: NetApp SMB Best Practices Guide