I was just at a VMWare user group in Seattle and they were showing an ISCSI solution by Equallogic. Equallogic makes REALLY nice ISCSI SANs.
The end user giving the presentation said ISCSI (with and without an HBA) works great and with no problems whatsoever. During the Demo they had 10 or more VMs running on two servers, somthing like that.
As for the pure number of VMs...not sure...but they were talking of binding multiple NICs as well.
Here is a coming Webinar that might be useful: http://www.eseminarslive.com/article2/0,2144,1969220,00.asp?partnerref=eqlpage_Home
Hope that helps,
PS I am not with EqualLogic. I don't even own any of their hardware.
iSCSI is definately able to run lots of VMs. The biggest limiting factor right now is that iSCSI support is only software based at this time. Once VMWare certifies some of the hardware iSCSI HBAs there should be no issues overall running this. I still prefer SAN based fibre HBAs, but as iSCSI matures it should definately continue to improve performance.
Another iSCSI company to look at is LeftHand Networks. They offer a San solution that clusters units to increase spindle count, performance and scalabilityy. They are availble as LeftHAnd Appliances and also are supported by HP offering a DL380 version. We have purchased several units for storage use, but are just getting in to vmware.
Another iSCSI company to look at is LeftHand
Networks. They offer a San solution that clusters
units to increase spindle count, performance and
The Equallogic units do the same thing, and Equallogic is a VMware partner or something according to their web site.
One of the selling features of both solutions is that they "stack" individual iSCSI chassis into huge arrays, and each chassis added to the group brings another 3 gigabit ethernet ports with it. As you increase spindles by adding more units, you're also scaling your connectivity throughput up! No bottlenecks at the network interfaces as you grow...
Demo'ed both boxes, ended up buying an Equallogic PS300e. No performance worries, we were running 7 or 8 test VM's with our primary Sybase DB on RH....better performance than our production NetApp.
I liked alot of what LeftHand had to offer, but the downside ended up being that it was built on a PC chassis, and relied on a single MB and Proc per SAN node. They offer their 'Network Raid' so you don't have a single point of failure due to the single MB and Proc issue...but in order to get the same TB we would have had to get 3 boxes....just ended up being too complicated.
Overall performance on both our NetApp using and ISCSI lun and the EQL were more than adequate. Our ESX hosts were Sun Fire x4200's with 2 GB Nics dedicated to the ISCSI connections.