Archive for the ‘Cloud’ Category

Bandwidth != Network Performance

You might think that if you want faster internet performance, you can simply get a connection to the internet that has higher bandwidth. When you get a “faster” internet connection you may observe faster downloads. But it’s less frequently the additional bandwidth, and more frequently reduced latency that actually produces increased interactive web performance. This [...]

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CPU Time stolen from a virtual machine?

Those of you studying the vmstat(8) man page may be wondering what the ’st’ figure is in the CPU column. The manual refers to it as “Time stolen from a virtual machine“. More specifically:
It’s the time the hypervisor scheduled something else to run instead of something within your VM. This might be time for another [...]

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Putting Entropy in the Cloud

I was browsing through twitter mentions of @adrian_otto and found one posted by Ian Thompson mentioning an article about weak randomness in the cloud. It suggests that because there may be insufficient entropy sources on a Cloud Server or instance that it may make it easier to guess random number sequences because different cloud servers [...]

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