iSCSI offload or software iSCSI?

[JonKemp]

I have just received 3 new Dell R610 hosts with the Broadcom 5709 onboard cards licensed for TOE and iSCSI Offload. We are running ESXi embedded 4.1 on these hosts and I have read that vSphere 4.1 supports Hardware dependant iSCSI connections through these cards. The question I'd like to pose is:

Should I configure the iSCSI connectivity usng the Hardware dependant feature, bearing in mind that the BCom 5709 only supports 1500 mtu in this configuration or disable the iSOE and use the VMware software initiator which will support 9000 mtu?

We are connecting to a pair of HP P4500 G2 iSCSI SANs. These and the networking switches can be configured to use 9000 mtu. The system is to be used as a Test\Dev environment so I do not have figures for the expected workload / IO load.

[a_p_]

The below is my personal opinion (not yet proved in a real live scenario by myself)

From what I read so far about using Jumbo frames is that there is no real benefit on a 1 GBit/s as opposed to a 10 GBit/s network. What I would probably do in your case, is to use the offload capabilities of the NICs and stay with the default MTU size.

André