Coraid :: The Linux Storage People

NAS File Sharing

•	Network "file" sharing is typically done using a protocol like Network File System (NFS) of SMB/CIFS. NFS/CIFS exports files over Ethernet using TCP/IP. Storage boxes that interface with the NFS or CIFS protocol are referred to as Network Attached Storage servers (or NAS servers).
•	NAS servers typically have a fixed number of disks inside their chassis, these are used in RAID sets to store files that are shared with NFS/CIFS. When the NAS server storage capacity is full, you must add another NAS server. This complicates the directory structure for clients sharing files over the network, making it hard to find files.
•	SourceTek's STS20 NAS Server is a Linux server without disks inside the server's chassis. It uses AoE to access disks on a storage network, creating a file sharing server with unlimited capacity.
•	AoE is used as the protocol to connect the STS20 NAS server to the block storage devices (the disks or RAID sets), and NFS and CIFS are used as the file sharing protocol for the clients (servers or PCs).
•	STS20 can create RAID sets that span multiple AoE device shelves (as shown in the diagram lblade 1.2) or it can access block storage that is already assembled into a RAID set (as shown in the diagram lblade 1.1).

Backup Storage

•	Backup Servers typically work in conjunction client backup agent software to create a centralize backup and restore storage system.
•	Backup Servers typically have a fixed number of disks inside their chassis, these are used in RAID sets to store the data collected by the backup agent software. When the Backup Server's storage capacity is full, you must add another Backup Server, and pay additional software license fees.
•	Backup Servers don't need disks inside (or if the disks are full, you may not need to buy another server). With AoE storage it is possible to assemble a backup server without disks inside the server's chassis. Simply use AoE to access disks on a storage network and create a backup system with unlimited expansion capacity.
•	AoE works naturally with most backup server software applications, since AoE storage appears like disks inside the server chassis.
•	The backup server can create RAID sets that span multiple AoE device shelves (as shown in the diagram lblade 1.2) or it can access block storage that is already assembled into a RAID set (as shown in the diagram lblade 1.1).