I can not seem to get jumbo frames to work on our Equallogic PS6000.  We have the following setup PS6000 -> Dell PowerConnect 6248 (stacked) -> Windows 2008 server.

The nics on the SAN are set at 9000 MTU, the ports on the switches are set at 9216 MTU and the nic on the 2008 server is set at 9014 with flow control RX & Tx Enabled. 

When the server connects to the SAN, the logs report iSCSI login to target '172.21.X.X:3260, iqn.2001-05.com.equallogic:0-8a0906-xxxxxxxxxxx-23a001a955452af6-server1' from initiator '172.21.X.X:49156, iqn.1991-05.com.microsoft:server1' successful, using standard frame length.

When I ping the SAN from the 2008 server with a larger packet of 8972 bytes it works fine.

C:\Users\system>ping 172.21.x.x -f -l 8972

Pinging 172.21.x.x with 8972 bytes of data:
Reply from 172.21.x.x: bytes=8972 time<1ms TTL=255
Reply from 172.21.x.x: bytes=8972 time<1ms TTL=255
Reply from 172.21.x.x: bytes=8972 time<1ms TTL=255
Reply from 172.21.x.x: bytes=8972 time<1ms TTL=255

Why 8972?  Some genius on the internet said to.  Any help would be greatly appreciated.