I am looking at getting a SAN for a virtualization project. I have been looking at an EMC NX-4 and also Netapp FAS 2020. I have spoken with some people about the EMC, but just spoke with a rep about the 2020 today. I have a questions about a dual head unit. What does this mean exactly? Is this like having a dual controller?
I was a little confused because on the NetApp I will need twice as many disks with dual heads. What advantages over an active/active configuration on an EMC does this offer? Disadvantages?
Also what kind of extra space do I have to plan for on the NetApp and EMC for things like snapshots? I know on the EMC there is a seperate array that is used for their OS. I know that I have seen things about the NetApp boxes to plan for a lot of spare space if running iSCSI and CIFS/NFS. How much space should be planned on?