Cloud firm cuts latency with PernixData flash caching software

Cloud apps provider Virtustream cuts VMware host latency by 96% with PernixData FVP flash caching software

Cloud applications provider Virtustream has reduced application latency by 96% and slashed costs on storage infrastructure after deploying PernixData FVP flash caching software to speed up data access on server hosts.

Virtustream is a cloud service provider that delivers enterprise-class applications, such as SAP, to hundreds of customers around the world from datacentres in the US, London and Amsterdam.

It runs its cloud services on VMware infrastructure with its own in-house written cloud management platform and uses a combination of IBM and Cisco servers with storage from Dell Compellent, NetApp and Hitachi Data Systems with datacentre connectivity via 10Gbps Fibre Channel over Ethernet.

Virtustream provides infrastructure to customers with SLAs on performance and, according to senior vice-president for solutions architecture Matt Theurer, the search for ways to ensure performance targets were met was the spark that led to deploying flash caching software.

“Storage is always a bottleneck, especially in virtualised and cloud environments where you always want more I/O and more density, but where disk spindle speeds cannot increase and performance per gigabyte is steadily decreasing,” he said.

“In those circumstances, we want to get every last drop of performance from the hardware we have. We were looking for ways to create scalable, flexible caching that scaled as our hosts did.”

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Virtustream wrote off the idea of all-flash arrays on grounds of cost and because they would run into the same throughput and processor performance issues as any array, as well as being distant from the host CPU, said Theurer.

“We had excess CPU cycles and wanted to find a way to utilise them,” he added.

Theurer’s team looked at a number of flash caching software products. Some were rejected for being read-only. Many were rejected because they needed to be managed at the virtual machine level. Virtustream wanted any caching solution to be transparent to the VM and not bound to back-end storage.

NetApp’s FlashAccel was rejected because it was limited to operation across a number of nodes and is tied to NetApp storage.

PernixData FVP was initially deployed by Virtustream as a proof-of-concept in a development environment, but was later installed across its server hosts.

It can be deployed in any server with flash storage to create a flash cluster. Data can be accelerated by policy on a per-VM or per-datastore basis with options for read, read/write and the choice of one to three copies of cached data replicated to multiple hosts.

Theurer said a key advantage has been to deploy disk storage as back-end bulk capacity while data access is speeded up at the host. Virtustream achieved a 96% reduction in application latency during periods of peak usage, he said.

“Customers are getting fantastic performance with one, two or three millisecond response times and we’re fully utilising storage infrastructure,” said Theurer.

“It’s not unusual for the typical SAN to get to 25% to 50% capacity and reach its performance limits. With PernixData FVP, we can’t reach the upper limit; we just can’t max out the storage system. We haven’t had to buy storage controllers since deploying PernixData.”

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