SAS is a bus which implements the SCSI protocol in a point-to-point fashion. The array you have is the effective equivalent of attaching additional hard drives directly to your computer.

It is not necessarily faster than iSCSI or Fiber Channel; almost any nearline storage these days will be SAS, almost all the SANs in production, and most of the tiered storage as well (because SAS supports SATA drives). I'm not even sure if NetApp uses FC-AL drives in their arrays anymore. I think they're all SAS, but don't quote me on that.

What differentiates a SAN (iSCSI or Fiber Channel) from a NAS is that a SAN presents raw devices over a fabric or switched medium rather than point-to-point (point-to-point Fiber Channel still happens, but it's easier to assume that it doesn't for the sake of argument). A NAS presents network file systems (CIFS, GlusterFS, Lustre, NFS, Ceph, whatever), though this also gets complicated when you start talking about distributed clustered network file systems.

Anyway, what you have is neither of these. It's directly-attached storage. It may work, but it's an unsupported configuration, and is only shared storage in the sense that it has multiple controllers. If I were going to configure it for oVirt, I would:

Attach it to a 3rd server and export iSCSI LUNs from it

Attach it to a 3rd server and export NFS from it

Attach it to multiple CentOS/Fedora servers, configure clustering (so you get fencing, a DLM, and the other requisites of a clustered filesystem), and use raw cLVM block devices or GFS2/OCFS filesystems as POSIXFS storage for oVirt.

Hans