Consolidation has emerged as a way to ease these problems. Instead of maintaining ad hoc IT infrastructures at each remote office consolidation moves the IT resources back to a main data center allowing centralized applications and data to be accessed remotely across a wide area network (WAN) link. Wide area file services (WAFS) is another key technology for this type of centralization allowing real-time read-write data access. Since data demands WAN bandwidth WAN optimization is equally important and uses a variety of technologies to pass more data in less time speeding data transfers and saving bandwidth costs.
But WAFS and WAN optimization products should be evaluated carefully. If you’ve reviewed the issues involved in any backup acquisition now you can read about specific considerations for WAFS and WAN optimization products. You’ll also find a series of thumbnail product descriptions to help you compare products from vendors such as Certeon Inc. Cisco Systems Inc. F5 Networks Inc. Juniper Networks Inc. Riverbed Technology Inc Silver Peak Systems Inc. and others.
Understand the difference between product types and terms. WAFS products typically allow for continuous read-write access to centralized data low latency and effective data transfer speeds similar to LAN speeds. WAN optimization products use compression and data acceleration techniques to pass more data using less bandwidth. These products serve two distinct purposes. Some WAFS products include WAN optimization features but it’s not universal and the two products can exist separately. Note: Vendors rely on their own unique definitions of these technologies. For example Cisco calls this wide area application services (WAAS). Always review all features before making any product choice.
Bandwidth and connectivity requirements. WAFS and WAN optimization products all rely on a WAN link so you should understand exactly which types of WAN attributes a product supports. Some products demand T1 connectivity while others work over an ordinary Internet connection. Evaluate the level of bandwidth needed to support each remote office or location. As bandwidth costs increase WAN optimization features can help to mitigate bandwidth requirements. It’s also useful to evaluate the supported transports such as multiprotocol label switching (MPLS) IP VPN satellite frame relay ATM or other supported transports to ensure that the product is fully compatible with your infrastructure.
Local caching and cache behavior. Connectivity and bandwidth are vital factors but it may be more important to evaluate the impact of connectivity loss. WAFS works by retrieving files from the data center across a WAN and caching those files on local storage where users can access the data quickly. Changed files can then be sent back across the WAN to the data center as bandwidth allows. But you need to know what happens when the WAN link is disrupted. Ideally any files currently in the local cache will still be accessible and the WAFS product will resynchronize its data with the data center once the WAN is restored. Also consider the impact of multiple iterations of a file — recognize how the WAFS product handles multiple people working on the same file simultaneously and how WAN disruptions will affect those activities.
Data reduction techniques. WAN optimization applies compression and data reduction techniques to reduce the volume of data that needs to pass between the data center and remote location. For example Availl Inc. claims a 95% reduction in traffic through byte-level differencing and compression. Cisco claims a 100:1 reduction in bandwidth utilization by eliminating redundant data and LZ compression. Citrix Systems Inc. claims an astonishing 3 500:1 reduction in data by applying a variety of compression/data reduction schemes. Data reduction will reduce bandwidth requirements but not all data compresses the same way. You’ll need to evaluate the techniques used in any prospective product and gauge its effectiveness on your typical data volumes.
Below you’ll find thumbnail descriptions of these WAFS and WAN optimization products: