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November 11, 2007

Network attached cache/memory for lower consolidation/virtualization costs

Many companies are consolidating their servers today. Rather than watch servers go underutilized whilst running a single application, they are consolidating multiple applications on to fewer boxes to save money and increase the average utilization of the servers.

This increases the CPU usage but memory can be a problem. Memory is not cheap. Even on blades, maxing out the memory capacity can be very expensive. Running multiple Java applications in their own JVMs on a single box uses up memory fast. Each one can take a GB or more of memory. If the application uses 5% of CPU on average then consolidating can push up the CPU usage but you may not be able to achieve 40-50% CPU usage because you may run out of memory first. 10 JVMs can easily take 5-10Gb of memory when running a biggish application. If the applications use caching then the memory usage may be considerable and result in either very expensive memory costs or fewer applications per server which works against a consolidation strategy.

Network attached caches such as ObjectGrid can help reduce memory costs considerably and thereby allow a successful consolidation strategy without incurring unreasonable memory costs. A cluster of ObjectGrid servers can run on a set of machines and provide a large network attached memory based cache for applications. This means that if an application needs a Gb of cache to run well then rather than have a Gb of memory per JVM, we can have a Gb of memory in total across the cluster which can result in a massive saving. If you have 20 machines then you may be able to run 20 objectgrid servers and use 500MB per box and still have 10Gb of network attached cache available for applications to use. This allows you to run more applications per server because the per application memory load is significantly lower.

ObjectGrid can easily pay for itself quickly when used in this manner. It cuts memory costs massively and allows more consolidation of applications on fewer boxes.

November 11, 2007 | Permalink


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