XenServer data stores are called Storage Repositories (SRs), they support IDE, SATA, SCSI (physical HBA as well as SW initiator) and SAS drives locally connected, and iSCSI, NFS, SMB, SAS and Fibre Channel remotely connected.
Background: The SR and VDI abstractions allow advanced storage features such as Thin Provisioning, VDI snapshots, and fast cloning to be exposed on storage targets that support them. For storage subsystems that do not inherently support advanced operations directly, a software stack is provided based on Microsofts Virtual Hard Disk (VHD)
specification which implements these features.
SRs are storage targets containing virtual disk images (VDIs). SR commands provide operations for creating, destroying, resizing, cloning, connecting and discovering the individual VDIs that they contain.
Reference XenServer 7.0 Administrators Guide: http://bit.ly/2d8uA7C
Also refer to the XenServer Hardware Compatibility List (HCL) for more details.