Рекомендация от Dell по использованию Jumbo Frames в SAN/iSCSI сетях

Jumbo Frames: Dell recommends that you enable Jumbo Frames on the switch ports that handle iSCSI traffic. In addition, if a host is using a software iSCSI initiator and NIC combination to handle iSCSI traffic, you must also enable Jumbo Frames on the NICs to obtain the performance benefit (or reduced CPU overhead) and ensure consistent behavior.

Note: Jumbo Frames must be enabled throughout the entire iSCSI SAN from the NICS,  Switches, and array ports, otherwise, behavior may be inconsistent. To simplify  troubleshooting initial deployments, make sure that NICs, switches, and MD3000i storage arrays are fully operational before enabling jumbo frames. 

Источник: http://www.dell.com/downloads/global/solutions/public/white_papers/IP-SAN-BestPractice-WP.pdf