I'm in the process of planning a Virtualization project and in doing research I cant seem to find a decent comparison of SAS vs iSCSI HBA. I am leaning towards Dell PowerVault MD3200 or MD3200i combined with 2 PowerEdge servers.

I understand the MD3200 is direct connected to the servers and the MD3200i is configured in a SAN environment and requires additional networking (to be implemented properly) than that of a DAS device.

Is there a real advantage using an iSCSI device over a DAS-SAS device?

 

Mark C.
 

Google DAS vs SAN to give yourself a little reading material, but in essense, you would normamly be talking DAS for local storage to one server. That being said, there are DAS appliances that have multiple controllers so multiple servers can attach. The more traditional method for attaching multiple servers to storage is the use of either a NAS or SAN. NAS has, to some degree, fallen by the wayside as SAN technology has become much more price competitive due to iSCSI. You don't need a special HBA for iSCSI as a regular NIC can be used. There are higher level NICs that are specialized for iSCSI (processor and tcp offload, etc...), but you would have to check with the storage vendor to see if those NICs are even supported. That, along with LAN separation, is you only requisite. LAN separation can either be done with physically separate switches (best practice) or creating a VLAN. It all depends on how many servers, SAN nodes, users, etc... are plugged into that one switch (just need to be carefull you don't oversubscribe the bandwidth off of the one switch).
Hope that helps.