The Cost and Peace of Mind of LAN Free Backups

Tuesday Oct 2nd 2001 by Drew Bird

Fibre Channel LAN-free backup offers all the management advantages of centralized backup approaches, and the performance capabilities of distributed backups. As the name suggests, LAN-free backups move backup data off the LAN and onto dedicated links that network servers use to communicate with centralized storage devices.

As the volume of data held on network servers continue to grow, and as access to this data is in demand 24X7X365, the challenge of time effective backups is a constant struggle. Server administrators have to toe the line between information protection and information access, and as the saying goes, you cant serve two masters.

It used to be that networks had a slow time or even a dedicated backup window, it was usually somewhere between the after work hours until the following morning. During this time, server administrators could busy themselves with backup procedures safe in the knowledge that no-one would notice the drop in server performance or the sluggishness of an network filled with data on its way to the tape drive. As long as the backup was complete by the following morning, everyone was happy.

Nowadays, many administrators do not have this luxury, as many companies do not shut down at the end of a workday, effectively eliminating the backup window. Even so, the backup has to be taken, somewhere somehow. The problem facing many server administrators then becomes this; how to protect the ever-increasing volume of data without compromising data access.

Most networks employ one of two types of traditional backup strategy. The first, and by far the most common, is a distributed backup system where each individual server maintains a local backup device. The second, more modern approach uses a centralized design where the backup device is located on a central server. Distributed backups work well in smaller environments, but as the number of servers increase so too does the cost and time involved to maintain such a system. Each server in a distributed backup strategy requires its own tape device and media set, which can become costly depending on the number of servers. Of perhaps more concern though is the management of numerous tape devices. Someone has to be responsible for loading and unloading each of the backup tapes. Its a simple task, but not one thats a good use of time or resources. Quite simply, the lack of centralized management make distributed backups impractical in larger networks.

A more centralized approach, while addressing the some of the administrative and cost problems associated with distributed backups, has its own disadvantages. When a single server is responsible for the backups, it demands considerable resources from the backup server, often leading to less than adequate server performance if the server offers additional services. Even more noticeable is the poor network performance caused by huge amounts of data being dragged across the network Additionally, because data is flowing into a single location, backups often flow into user uptime as the centralized device struggles to keep up with the demands placed upon it. For companies housing large amounts of data that require high levels of performance and availability, a better solution is needed.

This is where a Fibre Channel LAN-free backup solution comes into play, offering all the management advantages of the centralized approach, and the performance capabilities of distributed backups. As the name suggests, LAN-free backups move backup data off the LAN and onto dedicated links that network servers use to communicate with centralized storage devices. To do this, each server to be backed up needs a Fibre Channel adapter installed which connects to a Fibre Channel hub or switch at the other end. The switch itself is connected to disk arrays or tape libraries. A single server is then configured as a central management point for all of the other servers on the network. When the central server tells another server to send data, the data travels across the dedicated link, avoiding the LAN completely. As well as allowing the backing up of data to be controlled from a central location, the centralized server is also able to synchronize and co-ordinate the sequence in which servers send data to the backup devices, thereby maximizing efficiency and throughput.

LAN-free backups, while reducing congestion on the network, still suffer from a performance hit when servers spend their resources on the backup procedures, which is why some companies have taken the LAN Free backup approach one step further and introduced serverless backup. As the name suggests, the serverless strategy takes the processing away from the server and instead uses devices such as a dedicated computer or a Fibre Channel switch as the control point.

So, who is taking advantage of the backup strategies? Currently, the cost of implementing a LAN Free strategy is too prohibitive for many companies although proponents of the LAN Free approach contend that the savings gained from a reduction in workload from in IT personnel may justify the cost. Still, you have to pay to play and in an environment where $75,000 is entry level, the cost of admission is dear. That said, the knowledge that you have a solution that provides both information protection and information access may help you sleep better at night. As the old saying goes, you cant buy peace of mind.

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