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WAN file protocol optimization: Three ways to accelerate CIFS and NFS

View these three tips for accelerating file protocols CIFS and NFS over WAN.

One of the key trends in IT continues to be the consolidation of servers, storage and data from branch offices...

into central data centers. The benefits for this consolidation are clear: simplified IT management; increased data compliance and control; and reduced hardware, software and management costs.

However, centralization can create application performance challenges. Legacy file-sharing protocols such as NFS, the main protocol for *nix file sharing, and CIFS, the main protocol for Windows file shares, are very latency-sensitive and simply don't operate well over WAN connections. This is due to the way they rely on request-response chains to move data around. Hundreds of round trips may be required for just one simple operation. A file that would take milliseconds to open on a LAN could take minutes over a WAN. What companies need are WANs that function like traditional LANs. WAN file protocol optimization can tinker with the mechanics of the conversations in various ways to remove the chattiness of these protocols and soften the blow of the added latency.

Tip 1: Upgrade your applications, protocols and performance 

Most enterprise applications have transitioned to using Web technologies for delivery. For example: Document management systems such as Microsoft SharePoint, Documentum, Jive and Google Docs all transport over HTTP and SSL. Recent versions of Microsoft Exchange and Outlook have also moved from Messaging Application Program Interface (MAPI) to HTTP. Consider upgrading to current versions of your enterprise applications that use these more efficient Web protocols. Such upgrades will result in reduced WAN consumption and satisfied end users.

Tip 2: Think about priority

WAN optimizers can shape traffic and ensure that an organization has control over how its limited WAN bandwidth is used. This can mean guaranteeing that some applications (or devices, or users) get bandwidth, or it can mean limiting the bandwidth things get. Using them for file protocol optimization for legacy applications that rely on additional bandwidth can result in enormous performance improvements.

Tip 3: Speed up file transfers with compression, caching and prefetching

One of the key capabilities of optimizers is the ability to prefetch data. Optimizers understand when a file transfer is taking place, and they can prefetch part of or the entire file over the WAN to the remote optimizer as quickly as possible. Protocol communications at the remote end destined for a server in the data center are intercepted by the remote optimizer, which generates the appropriate response so that much of the chattiness of the protocol never touches the WAN. The remote optimizer delivers locally the file that the protocol is trying to transfer.

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Optimizers also have the ability to reduce the amount of data being transferred by using caching and compression techniques. Optimizers intelligently store data in caches and compare files that are being transferred with what is available in their cache at a byte or block level. This means that any data that has already been sent -- even as part of a completely different file -- does not need to be present. In some cases, this can lead to as much as a 95% reduction in WAN traffic.

By using WAN optimizers, organizations can extend their investments in legacy applications and file systems and still reap the rewards of centralization. Organizations that have yet to centralize all branch applications and file servers should consider how these three file protocol optimization tips can enable centralization.

This was last published in November 2012

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