March 17, 2005

By Jason Deign, News@Cisco

Is it any wonder large organizations are worried about data storage? The average document, spreadsheet or presentation can be replicated tens if not hundreds of times as it is passed from one person to another, for reviewing, editing, additions and subtractions.

The reason data files have traditionally reproduced like coat hangers in a wardrobe is that, in many cases, accessing a single file many times over simply was not practical.

If the original file was on a server in a different office, the latency problems associated with access over a WAN became excessive. In addition, it is difficult to ensure that the user is accessing the most recent copy of the file.

That was until a development called Wide Area File Services (WAFS), launched by Cisco Systems® last year alongside the Cisco FE 511 File Engine.

WAFS' impact on storage networking could be compared to that of jet-propelled planes on transatlantic travel, cutting down the transport delay across a WAN so that files can be opened seven or eight times faster than at present and saved in one-fifth to one-eighth of the time.

"The technology brings every file in a business within reach of a single user, employing a number of clever tricks to ensure someone can work on a file stored hundreds of miles away just as if it were on the server next door," says Marcus Chambers, Europe, Middle East and Africa (EMEA) director, storage optical and WAFS, at Cisco.

Besides cutting down on overall storage requirements, WAFS simplifies disaster recovery and backup procedures because branch-office files can be stored in central data centers instead.

This could represent a significant bonus. According to Enterprise Strategy Group in the US (as quoted in Computerworld, December 2004), up to 70 percent of the data in an organization is currently held in branch offices.

In addition, tape backup services can be run centrally and File Engines within branches can double up as print servers, resulting in lower costs and reduced administration.

Collaborative working is enhanced, too, because edits, additions and approvals can all be carried out on a single file, regardless of location, without having to deal with multiple copies that then have to be collated.

The Cisco technology achieves all this in two ways. Firstly, WAFS provides a way of extending the two main LAN-based file system protocols, Common Internet File System (CIFS) with Microsoft Windows and Network File System (NFS) with UNIX, over a WAN.

Both NFS and CIFS are not intended to operate over WAN links and most applications that access the file system assume LAN-based access as well.

There are hundreds of CIFS client-server messages in a typical Microsoft Word 'file open' instruction and 40 percent are signaling messages that are a few bytes in length and cannot be compressed. Adding more bandwidth on the network will not address the latency problem.

To address this limitation, Cisco WAFS uses a proprietary adaptation protocol layer between edge and core file engines.

Secondly, Cisco file engines manage to do an ingenious amount with copies of files or parts of files cached locally.

Up to 90 percent of client messages are read or access requests that can be handled locally by edge File Engines; only edits need to sent across the WAN and these are transcribed asynchronously to the master document in the data center.

"The system maintains a series of policies and algorithms to ensure cached data is always fresh and that when a user opens a file, it is always the latest version since the last time the file was closed," says Christopher McIntire, business development manager for WAFS in EMEA.

Cisco file engines are designed to sit at either end of the WAN connections between branch offices and headquarters or data centers.

For ease of deployment and installation, each file engine ships preloaded with WAFS software that allows it to run as an edge file engine, core file engine or WAFS central manager.

"We have seen a clear demand for users to implement centralized information management policies to encompass all data within the company," says Hamish Macarthur, managing director of analyst group Macarthur Stroud International.

"The challenge is how this can be done effectively to include all regional and branch offices. Cisco's WAFS solution enables centralized management of the vast number of office documents, many of which could be critical for legal and regulatory purposes. "

The developments in storage area networking announced by Cisco last year followed the company's acquisition of Actona Technologies, a developer of wide-area file services software, in June 2004.

"Until the availability of WAFS technology, there was no real practical way to solve the latency issues involved in accessing files over long distances," says Steve Duplessie, senior analyst and founder of the Enterprise Strategy Group.

"Staying at a higher applications level, and not just focusing on the pipe itself, is a critical ingredient to be able to successfully pull this off.

"Consolidating remote branch-office file services and storage to a central location will make it easier for IT administrators to manage these discrete resources while allowing them to take advantage of the data-protection infrastructure that is readily available in the main data centers."

George Kurian, vice president for the Caching Services Business Unit within Cisco, adds: "The large amount of mission-critical information that resides on employee desktop, laptop computers and workstations needs to be shared, backed up, and archived.

"Today's distributed branch office storage management methods are complex and expensive. Providing intelligent network services so distributed enterprises can centralize file servers and storage, and better protect and cost-effectively manage their remote office data, is critical.

"This technology is a best of breed wide-area file services solution, enabling storage consolidation while providing 'LAN-like' file access over a WAN."

Jason Deign is a freelance journalist located in Barcelona, Spain.