By Greg Schulz, Server and StorageIO @storageio
Serial Attached SCSI (SAS) is better known as an interface for connecting hard disk drives (HDD) to servers and storage systems; however it is also widely used for attaching storage systems to physical as well as virtual servers. An important storage requirement for virtual machine (VM) environments with more than one physical machine (PM) server is shared storage. SAS has become a viable interconnect along with other Storage Area Network (SAN) interfaces including Fibre Channel (FC), Fibre Channel over Ethernet (FCoE) and iSCSI for block access.
Various storage options for servers include shared external DAS, networked SAN (iSCSI, FC and now SAS) or network attached storage (NAS such as NFS and Windows CIFS file sharing). In some cases, storage is moving offsite utilizing public or private clouds and managed service provided (MSP) capabilities. Also, it is important to keep in mind that DAS does not have to mean dedicated internal storage; it can also mean external shared direct accessible storage using SAS, iSCSI or Fibre Channel in a point to point topology configuration.