Click for larger, more confusing view

Virtual Geek has an amazingly insightful post combining multiple presentations and points from representatives from EMC, MVWare, NetApp, Dell/Equalogic, HP/Lefthand, and some other folks in the business. As you can see by the names involved, we’re talking about most every major virtualization storage player in the industry today – and they’re here to help us make heads or tails of iSCSI storage. You’ll even be able to make sense of that diagram above after reading:

As discussed earlier, the ESX 3.x software initiator really only works on a single TCP connection for each target – so all traffic to a single iSCSI Target will use a single logical interface. Without extra design measures, it does limit the amount of IO available to each iSCSI target to roughly 120 – 160 MBs of read and write access.

This design does not limit the total amount of I/O bandwidth available to an ESX host configured with multiple GbE links for iSCSI traffic (or more generally VMKernel traffic) connecting to multiple datastores across multiple iSCSI targets, but does for a single iSCSI target without taking extra steps.

Here are the questions that customers usually ask themselves:

Question 1: How do I configure MPIO (in this case, VMware NMP) and my iSCSI targets and LUNs to get the most optimal use of my network infrastructure? How do I scale that up?

Question 2: If I have a single LUN that needs really high bandwidth – more than 160MBps and I can’t wait for the next major ESX version, how do I do that?

Question 3: Do I use the Software Initiator or the Hardware Initiator?

Question 4: Do I use Link Aggregation and if so, how?

Here are the answers you seek…