How fast cache works

I was able to max out the RAID set with an averaged 60s peak of IOPs the collector used averages every 60s; therefore the effective peak number is probably a lot higher. This environment has an average utilization of The second very important part of this analysis is to understand the response time during the workload. Storage latency is responsible for most performance issues in VDI deployments. High latency in VDI is directly perceived by the end-user characterized by slowness, lagging or long time to refresh screen.

The recommendation from VMWare for virtual workloads is never have average above 10 ms, or peaks above 20 ms. The graph below demonstrate that response time has an averaged peak of 3.

In fact; the total average was never beyond 2 ms. Nonetheless these results are not valid unless a number of other variables are clearly disclosed.

All these variables are essential in estimating storage capacity and performance. That counteracts the reduction in overall write cache pages. By now you are probably asking why I went from disbeliever to evangelizer.

It just makes the whole sense in the world with few exceptions. How does FAST cache pre-cache blocks before a write is committed by the virtual desktop is those blocks are from new VM?

There are, off course, a number of nuances about how effective FAST Cache is for different workloads. Things like data locality, active data, and pool tier sizes are some of the variables. However, for VDI workloads it works like a treat!

From the best of my knowledge, there are many solutions on the market that promise to offload Read IOs, but not many can optimally handle Write IOs. FAST cache is a great solution but it should not be the only and foremost solution to help in reducing IO impact and improve performance. Skip to comment form.

Peter Wilson I did a bit a google but could not fully understand if IBM EasyTier is a Fully Automated Storage Tiering solution that move blocks across tiers overtime during shedulled times overnight , or if it moves data dynamicaly and real-time to SSD during the day when required. Would you know? Have you ever looked at the Whiptail Technologies solution? Dave Whiptail is a SSD only storage appliance solution.

In non-persistent VDI deployments performance is key and capacity is secondary. In this cake Whiptail or any other similar solution will provide you with enough IOPs. The storage appliance deployment model makes sense for non-persistent if you confortable dedicating storage arrays for VDI only.

Who is Whiptail? Fill in your details below or click an icon to log in:. Email required Address never made public. Name required. Search for Twitter LinkedIn WordPress. Follow DavidRing. FearDamhan Random Technology thoughts from an Irish Virtualization Geek who enjoys saving the world in his spare time.

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