Archive for the ‘Linux’ Category

On Linux RAID and LVM

Sunday, March 29th, 2009

In an earlier blog entry on how we evaluated various virtualization technologies, I also wrote about using Linux Software RAID (md) instead of FAKERAID/HOSTRAID.

RAID as most know it is a technology that allows the grouping for multiple physical hard drives into one logical drive for either redundancy, performance or both. But the technology is not without caveats.

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The Cost of High Availablity

Saturday, March 28th, 2009

So here I am once again sitting in a meeting room of an ISP with some 4 or 5 executives, salesguys , product guys and a bunch of other engineers discussing how we should set up HA. The entire project’s network was drawn up on a white board and three engineers stood by the sides. They were pointing at every link and node in the diagram and asking, “is this HA?”

You’d be surprised how long these discussions can take. It went on for about two hours and one dude finally broke the tension and stood up, and we thought he was headed for the washroom but he said instead, “what’s the point of all these? With all these costs, will the service even sell?”

He hit the nail. The room was quiet for a moment.

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