We are thinking to direct attach two Servers to a FAS2020 either using ethernet cable (NFS o iSCSI configuration) of FC but not using Ethernet LAN Switch or FC Switch like I said Direct Attach like the picture I uploaded
Would you mind letting me know if this config could work? Is this configuration supported?
what are the disadvantages of using this?
I know to have completely redundancy I'm going to need a Ethernet or SAN Switch but for this customer $$$ is not an option right now
I dont see where the ethernet (either NFS or iSCSI) would be a problem except for management of the Controller. NFS would probably be better as iSCSI may not play well and I dont know that it would appreciate the single path for failover. You would probably have to use the CLI for managing everything. FC is another story. I thought that on the FAS2020 the FC ports were setup for initiator mode (meaning to connect to disks) and not target mode (where servers can connect to it). I'm not sure if that is changable on the 2020 or not. Why is it you dont want to use any switches? Is it just a cost issue or space?
It also depends on what kind of data you are putting on the FAS. If it's either SQL or filesystem data, I'd go NFS because then you dont need to worry about allocating space to Fractional reserve (per every best practice i've been provided says to ensure 225%). If it's exchange then it must be block protocol so iSCSI or FCP. NFS tends to get better dedupe rates in my experience.
You can mix both connections too, let's say, use NFS for your VMs datastore and FC for Databases and Exchange. If you use NFS for VMware Datastore, is a good idea to split the Datastore and create 2, since you are connecting the ethernet ports straight to the filer you won't be able to create VIFs, you can put half of your VMs in one datastore and the other half on the second datastore, or even better, estimate the throughput needed for each VM and split it based on throughput, you will need 2 different networks, one for each interface, and create static routes to direct the traffic of each network to the proper network interface, it would be a good idea to add a vm based router (Vyatta does a good job) on your VMware servers to be able to access the filer outside the VMware hosts.