iSCSI Storage Planning

[crhill]

We are currently reviewing our VMWare configurations with reguards to our SAN. I have a couple of questions.

1. Is there still a throughput limitation per target in VSphere ESX 4.0 as there was in ESX 3.5. Has that been addressed so that it is possible to have 1GB Multisession connections as you can with the Microsoft iSCSI Initiator?

2. What is the best practice when it comes to the use of Extents to build the DataStores?

Thanks so much any information on this.

[RussellCorey]

With iSCSI MPIO its possible to drive more than physical wire speed of a single link to an iSCSI device provided you're using a supported storage array.

Configuration details here:

http://www.vmware.com/pdf/vsphere4/r40_u1/vsp_40_u1_iscsi_san_cfg.pdf

Regarding extents, there is a religious debate raging on that very issue. Extents can mean more LUN queues but more devices to manage.

With vSphere you can grow VMFS without using extents and iSCSI storage is cheap generally speaking so you shouldn't need to worry much about running short of datastore space.