Dell Unity: VNX: Performance Impact When Using CIFS Encryption Protocol Feature
Summary: Utillizing protocol encryption for CIFS on Unity or VNX Codes will degrade "write]" performance. (User Correctable)
Symptoms
The customer (Unity or VNX) can choose to implement Protocol Encryption under CIFS Share > Advanced:
Turning this flag on will have a negligible impact when CIFS is using a gigabit interface.
However, if the interface is configured with a 10 Gbit link (and CIFS clients are similar), the customer will experience a significant write performance decrease when the flag is on.
With the flag off and a 10 Gbit link, write performance is approximately 450 to 550 MB/s sustained throughput in large file writes.
When the flag is turned on (a client remount of the share is required), write performance decreases to 80 ro 150 MB/s.
Cause
The issue is related to the underlying algorithm used in the encryption process.
See the notes details for more information.
A similar indication has been provided by Microsoft: SMB Security Enhancements
Resolution
Workaround: Turn off Protocol encryption on the share level to avoid this impact.
Fix:
Unity release 4.2 contains a major performance increase for protocol-encrypted shares.
Contact Dell Technologies Support and quote this service request for more information if required.
Additional Information
Customer who would like to obtain further information on this limitation can contact Dell Technologies Customer Service and quote this Knowledge Base article.