Stefan's recommended approach:
For performance consulting, begin by asking whether they have high server load or just slow page loads. In the latter case we must first find out if it's the server or something else yslow can tell you.
In the case of high server load you should ask for the slow log. It would be nice if they had monitoring data for cpu ram and so on. Don't ask for full access to the data first. Some companies are really cautious about that and it's not necessary to get access for a starter.
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