While googling EC2 i saw a few unanswered questions about ec2 being slow. I found this which says your EC2 instance may run for a second or two then stall for just as long:

the catch with the micro is 2 ECUs for short periodic bursts...
a micro-instance [may] run fairly fast for [a short while], then slow down

Is there any truth to that? If i have one reserved instance and it is the only instance of my website would i get slow performance?


The issue with the micro is, as that article says, the the ECUs are for bursts, so if you are something data-intensive, you may see that behavior.

From EC2 Instance Types:

Micro instances may opportunistically increase CPU capacity in short bursts when additional cycles are available. They are well suited for lower throughput applications and websites that require additional compute cycles periodically, but are not appropriate for applications that require sustained CPU performance.

However, the other sizes don't use those "burst" ECUs so I would not expect to see that behavior on, for example, a small instance.

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I used the ping command with the -t option to continuously get responses for a 24hour period. I redirected the output to a file for later review. I did this with a "micro" instance, and then again with a "small" instance.

With the "micro" instance, I found pauses of 20 to 55 seconds, 7 times in that 24 hour period.

With the "small" instance, I found no pauses at all in that 24 hour period!

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  • Very good to know – user274 Jun 29 '11 at 21:06

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