Benefits of AVFS
AVFS - Ardis Virtual File System - is innovative technology that combines the intelligence and ease of use of NAS with the speed of a SAN with many benefits
- 3 times faster than traditional NFS and SMB/CIFS storage
- Using existing Ethernet infrastructure
- Transparent to users and applications
- Enables both Project and File Level based Sharing
- Windows, Mac OSX and Linux client support
- Capable of providing clients with AVFS access
- Storage server support more clients, users and other applications than NFS or SMB/CIFS based systems
What is the difference compared to a NAS?
Let's take a quick look at how AVFS accelerates network-attached storage with iSCSI. A Windows, Mac or Linux client accesses an AVFS solution over standard Ethernet wiring and switches. It uses the iSCSI protocol to transfer data over TCIP/IP and allows two hosts to exchange data at high speed. The only moving parts of an AVFS solution are:
1 AVFS software installed on the client.
2 A storage server which maintains the file system and handles the AVFS protocol and file system and provides the storage.
The AVFS protocol explained
NAS is fundamentally slower than iSCSI due to the chatty nature of high-level NAS protocol handling. iSCSI operates over the same Ethernet infrastructure and is a fast and efficient data transfer protocol. The combination of iSCSI for fast data transfers, and NAS for file system protocol awareness is used in the AVFS protocol to make a system with NAS functionality that runs at much higher speed.
The diagram shows how this works. With typical file access the NAS system is burdened by its metadata protocol overhead for each data transfer.
In comparison, the AVFS protocol incurs protocol overhead only at the beginning of each file access. After that initial handshake, data transfers run quickly and efficiently over iSCSI. Because AVFS can transfer more file data over a shorter period of time, AVFS has a performance advantage over traditional NAS access.
Large benefit in CPU utilization
AVFS is not only faster than NAS, it is also much more efficient. NAS protocol handshakes between NAS clients and an NAS server can consume a lot of CPU cycles, swallowing CPU resources needed for the client applications.
Switching to the AVFS protocol reduces the burden on NAS clients (approx. 7x less) and the storage server (12x less) by minimising the amount of protocol handshakes per block of data transferred. As a result, more clients can share the same storage system and more CPU cycles remain for client applications.
It is clear, that AVFS moves more data in less time.
Now what does this mean for professional Video, Film and Audio users?
NAS disadvantages in professional Film, Video & Audio
This table shows a list of video and film formats in use today. It is by no means complete, but it certainly shows the large spread in bandwidth going from MPEG-2 video to 4K for film.
Today almost all companies have a standard Gigabit Ethernet (GbE) network installed. The maximum theoretical bandwidth then between two network nodes is 125 MByte/sec. when using NAS normally much lower data rate is obtained. According to the table this is okay for a number of compressed video formats.
However due to inefficiencies in NAS protocols a powerful storage server is required to accommodate even a limited number of clients using high quality compressed video streams. This increases storage server costs. On the client desktop a considerable percentage of CPU time is needed to handle NAS based communication, which limits the number of video streams/layers available and often introduces latency when using transport and scrub controls.
Traditional SAN in a Film, Video or Audio environment
To overcome these bottlenecks AV and Film companies who can afford this use SAN based solutions. As mentioned before, in a traditional SAN system there is a separate data and communication or metadata path (see the figure) with Fibre channel for the data and Ethernet TCP/IP for the communication or metadata path. Handling two completely different network infrastructures can be difficult.
To make matters worse often an additional server is needed to handle the metadata traffic via the communication channel. So here we are with a Fibre channel network, an Ethernet network, a storage server and a metadata server. For many pro Video, Film and Audio companies such a set up is too expensive and complicated to install, operate and maintain. Any failure in such a set up to quickly identify a problem requires highly qualified technical personnel which is not always available.