Simple Connections

• Coraid EtherDrive AoE storage can be directly connected to a server using Ethernet.
   
• Disks can be accessed individually identified by their shelf and slot number. Coraid refers to these AoE devices as storage "physical LUNs". For example a disk in slot #4 of shelf #1 would be accessed on a Linux system as /dev/etherd/e1.4, (also referred to as EtherDrive LUN e1.4)
   
• AoE target devices are just like local disks. They can be used in addition to disks that may already be installed inside the server chassis.
   
• RJ-45 Gigabit connections must use CAT6 Ethernet cables to insure full operating speed. Cross-over cables are not required, since the Gigabit interface on Coraid's appliance auto senses Ethernet cable polarity.

• Coraid SATA+RAID (SR) EtherDrive Storage Appliances include RAID controller functionality within the chassis to allow one or more RAID sets to be accessed as "logical" AoE devices called "LUNs". (ie. LUN 1.1 shown here is a RAID5 made up of 5 disks in slots 0, 1, 2, 3, and 4, and accessed as one large block storage device, such as /dev/etherd/e1.1)
   
• A simple console port command line interface is provided on the Storage Appliance to configure the RAID setup.
   
• RAID can also be done from the host, using server RAID software.

Etherdrive Storage Appliance with internal RAID

• Using standard Ethernet networking (ie. Ethernet switches) the number of AoE storage devices can be expanded.
   
• Each EtherDrive storage appliance is assigned a unique shelf number.
   
• AoE packets are standard Ethernet frames, and they can share a LAN with other LAN traffic, however Coraid recommends a separate storage network to insure the highest storage access performance. (ie. separate from the client LAN traffic, as shown in the diagram)

Storage Shelves numbered 1, 2 and 3

• Using standard Ethernet networking multiple servers can access the same storage network.
   
• Storage is not captive to one server, therefore if a server failure occurs, its storage can be mounted by a backup server.
   
• Using Ethernet you can construct redundant connections between servers and storage, eliminating single points of failure.
   
• Clusters of servers can share common storage using cluster filesystems.

Shared Storage Pool