I disabled Jumbos on the Broadcom and it works fine.

On the switches (dell iscsi switches) all ports are configured with flow control and mtu 9000.

A dell engineer configured it and told us to set all nics to mtu 9000 if we get new servers.

Our vSphere Cluster works fine with mtu 9000 ...

I thought, that jumbo frames are a "must have" for high performance iscsi .

Thanks!

The switches are PowerConnect 5448.

Should i buy Intel NICs next time for ESX and Windows machines?

I thought that MTU9000 will work on the broadcom NICs because i was able to set it ;)

michael

You are right, in Switch Configuration Jumbo Frames are "enabled" for the whole switch.

Do you think that the latest firmware and driver from the broadcom website will let me use MTU 9000 in iSCSI Offload Engine?

I Would like Dell to publicate documents with the "best" settings for famous NICs.

Sometimes you read about disabling LSO or all offload features, but there is no document from dell which tells me the best settings for my NIC (in NIC-Mode).

Here is a config for our switches with vlan1 an jumbo: en.community.dell.com/.../configuring-a-powerconnect-5424-or-5448-switch-for-use-with-an-iscsi-storage-system.aspx

With Powerconnect 5xxx i thinks there will be nor problem with jumbos on vlan1. Its a iSCSI Switch with only iSCSI traffic an only one vlan.

In an equallogic configuration guide from 2009 they only wrote the commands to enable jumbo frames on this switch.

For some cisco switches they wrote that vlan1 can not be used for jumbo frames.

A Dell engineer installed our first ps6000e with two of these switches an left all ports in vlan1(default).

Was this a mistake?

michael