Shared Nothing architecture

Shared Nothing, the term is used in clustering model, eg. Exchange, DBMS, etc. There any 2 main kinds of resource sharing between servers in cluster model.
1. Shared Nothing: in this model, the servers in cluster need to communicate through some other kinds of connection like: Network, heartbeat to share and access information
2. Shared Resource (i don't remember, will update later) in this model, the severs in cluster share harddisk, memory, etc. it can boost the performance of the system, but the trade off is single-point of failture

FreeNAS: another option for clustering environment

If you ever try to install the clustering environment like Exchange, MSSQL, you will fight with the problem of installing quorum disk. And the problem going bad if your server doesn't work well with NAS (HBA, etc. compatibility issues)

Long time ago, freeNAS was born, along with him was openfiler, etc. these are the simulation for NAS that was shipped with iSCSI, and many other protocols like: FTP, Samba, CIFS, etc. and a Web-based administration tool. And to make more convenient, they was shipped with VMware appliance as well... cool !

And you don't have to invest any NAS device, you just download the ISO (Live CD) or the VMware appliance of FreeNAS, turn it on, configure it! and you will have a NAS device that working through the iSCSI protocol

The remain, is to download iSCSI initiator (Microsoft provides one), and free on many Linux distribution. Configure it to work with your new NAS. You can map 1 iSCSI disk (on your freeNAS) to as much server as you want... you have your own Quorum disk

It works for both Windows, Linux as well. Beside that, freeNAS has many interesting features like: authentication through Active Directory, work as file server, scheduling for backing up, it is built on FreeBSD

Good luck!