How replication acceleration still saves SAN costs

closeThis article could be out of date, as it was published 9 months 10 days ago.

Recent talk regarding WAN optimisation suggests that network optimisation features provided by SAN vendors are eliminating the need for replication acceleration.

At first glance, the position sounds compelling. Deduplication, compression and TCP optimisation, major features of WAN optimisation, are being bundled in many storage area networks (SANs).

So why bother with WAN optimisation?

The reality, though, is that most SAN platforms don’t include the ability to accelerate replication to remote SANs effectively. Many that offer features such as deduplication and compression are unable to apply them during data replication, where it’s needed most. Or where they are providing deduplication, they apply this feature at a block level that has low value in modern data environments with high rates of change.

I have seen replication acceleration eliminate over 75 per cent of the network bandwidth consumed by this already ‘deduplicated’ SAN data. The bandwidth savings result from a number of factors, but most notably the accelerator’s ability to deliver byte-level deduplication and wire speed compression to deliver the SAN’s data efficiently over the WAN.

And while almost every array allows IT specialists to modify the TCP window size and, in some cases, customise more advanced TCP options, arrays cannot deal with poor quality or shared networks. A large window size is fine until the network starts dropping packets or reordering packets to the extent that the receiving array thinks there is corrupted replication data.

In my experience with thousands of enterprise networks, they frequently suffer packet loss, particularly under the high load normally associated with replicating SAN data. When combined with any sort or latency, the resulting performance degradation can be catastrophic to Recovery Point Objectives (RPOs).

The traditional solution for this challenge was to provide dedicated high-grade links for SAN replication. However, with ballooning content and big data causing replication volumes to explode, this option is becoming too expensive for most organisations.

So unless SAN replication incorporates over the wire error or packet correction, an accelerator is required to address this issue and maintain RPO performance at a reasonable network price point.

So the current generation of replication acceleration is not just about deduplication, or window size, or even compression. It’s about the entire suite of enhancements that drive high performance and allows organisations to meet or exceed their RPOs at an affordable network cost.

If they cannot meet an RPO, or protect all the organisation’s data, or move that data over distance to assure its viability in the event of a local incident, it doesn’t matter if the data is deduplicated or optimised on the SAN. Seeing customers deploy replication acceleration in less than an hour and achieve performance figures that seemed impossible, is a very satisfying experience.

So I agree with testing WAN optimisation first before buying – because with the latest WAN acceleration software downloadable for free 30 day trial, organisations really should explore the potential.

By Brian Grant, Director Oceania, Silver Peak

Follow Us
on Google+
Sponsored

Review: Sony Xperia Z2

NetGuide Smartphones are all about compromise these days. Fitting a hi-res screen, camera and huge battery into increasingly lighter handsets isn’t easy, and usually, something has to give.   Read More →

Review: LifeTrak C410 Fitness tracker

NetGuide The C410 is a fitness tracker first and a watch second. Because of this it not only tells the time, but also tracks almost everything a fitness nut would need to know.
Amongst the many stats tracked are Steps. Calories are measured too as are distances covered. There’s a sleep tracking function, plus heart rate monitoring.   Read More →

Android App Review: Writing Prompts

NetGuide Writing Prompts is one of those obviously-named apps that gives you exactly what the name suggests and nothing more. If you want some help getting started with your creative writing, then the Writing Prompts app might be able to help.   Read More →