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We have a server system that currently consists of 1 Apache server that is attached to a load balancer and one MySQL server that is by itself. Both servers are AWS Micro Instances.

Everything is running smoothly so far, but I want to be smartly pro-active in upgrading the servers. I have been running "top" to see the CPU and memory usage, but that won't do me much good if I don't know when I should take action.


Currently the CPU usage sits around 0.0 - 0.7% but can jump up to 60% for an instant.

The memory reads: 608732k total, 601556k used, 7176k free, 38768k buffers


The CPU is between 0.0 - 1.0 % at almost all times

The memory reads: 608732k total, 540772k used, 67960k free, 155896k buffers

So... there is more free memory on the Apache server. That is great, but what can I watch for as an indication that I should be upgrading? With the Apache server I can add more instances to the Load Balancer in a pinch, but I don't want to get caught with the MySQL server.

Any insights you have would be greatly appreciated.

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up vote 0 down vote accepted

First, install a package like sysstat to monitor the machine's load. You are interested mostly in peak loads (say over a week/month). If the load approaches the machine's capacity, it is time to get a bigger one/a sibling behind load balancing. A trend over a longish period tells you when it will be time to upgrade.

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