san or NAS

SAN (Storage Area Network) solutions are usually built around expensive Fibre Channel adapters and switches, while frequently requiring a separate Ethernet metadata network from the dedicated Fibre Channel data network. A SAN presents itself to the client as a local disk, allowing the client to deal directly with the file system with very little latency. SAN storage systems only understand block data, leaving file-system concerns to the client computer.

NAS (Network Attached Storage) systems are relatively simple and easy to manage, although, they are much less efficient at utilizing IP bandwidth at approximately 50-70% of what is available over the Ethernet connection. A NAS appears to the client computer as a File Server, requiring the client to map a shared network drive. A NAS understands files and metadata while providing both storage and file-system.

Due to the fact that NAS systems are file aware, they operate at a higher layer and for this reason they introduce more latency into the read/write process. Because SAN storage operates at a lower layer it is substantially faster. For years, the burning question has been ‘which to use - SAN or NAS?’

DDP (Dynamic Drive Pool) is an IP-SAN based solution representing the best of both worlds, all from one box and on one Ethernet network. With the Ardis Virtual File System and iSCSI protocol, DDP is able to use almost 100% of the available Ethernet bandwidth. In contrast to most NAS systems in the market, DDP drives behave the same way as local drives, with no latency or lag.


iSCSI (Internet Small Computer Systems Interface) is a block level SAN protocol like Fibre Channel, except that it uses traditional Ethernet networking at 1Gb/s, 10Gb/s, 40Gb/s and 100Gb/s speeds. NAS protocols are fundamentally slower than iSCSI due to the chatty nature of the high level protocol handling. iSCSI operates over the same Ethernet infrastructure as NAS, but it is a more fast and efficient data transfer protocol.


AVFS (Ardis Virtual File System) is an innovative technology that combines the intelligence and ease of use of NAS with the speed and performance of an iSCSI block level SAN. AVFS acts as an integrated metadata controller inside of DDP; it is responsible for managing access on the Ethernet SAN providing simultaneous Read/Write to everyone.


AVFS is not only faster than NAS, it is also much more efficient. Protocol handshakes between NAS clients and NAS servers can consume a lot of CPU cycles, swallowing CPU resources needed for the client applications. Using AVFS reduces the burden on would be NAS clients by approximately 7x and on the storage server by 12x, thus minimising the amount of protocol handshakes required per block of data transferred. As a result, more clients can share the same storage system and more CPU cycles remain available for client applications.

DDP allows full project and file level based sharing and is packed with the most innovative technologies available for Post Production and Broadcast. People working with multi-media appreciate that desktop drives need to regularly handle large amounts of data. Multi-media software such as those from Adobe, Avid, Apple, Grass Valley, Autodesk, Image Systems, Fairlight and other video, film and audio editing applications frequently require direct high-speed shared access to drives or volumes with minimal latency.

Added to the everyday demands of multimedia are issues such as capacity limitations and back-up; data-hungry multimedia applications can easily run into capacity limitations and we are all familiar with the worries presented by the need for regular, reliable back-ups.

As a result of the introduction of Ardis Technologies AVFS/iSCSI system, companies can now use SAN with NAS simplicity and functionality. AVFS combines the performance benefits of the iSCSI SAN protocol with NAS simplicity using a single Ethernet network. It’s the best of both worlds!