MySQL Performance Blog

Quite common beginners mistake is not to understand how indexing works and so index all columns used in the queries…. separately. So you end up with table which has say 20 indexes but all single column ones. This can be spotted with a glance view. If you have queries with multiple column restrictions in WHERE clause you most likely will need to have multiple column indexes for optimal performance. But wait. Do not go ahead and index all combinations. This would likely be poor choice too

So you need to design highly available MySQL powered system… how do you approach that ?
Too often I see the question is approached by focusing on expensive hardware which in theory should be reliable. And this really can work quite well for small systems. It is my experience – with quality commodity hardware (Dell,HP,IBM etc) you would see box failing once per couple of years of uptime which is enough to maintain level of availability needed by many small systems. In fact they typically would have order of magnitude more availability issues caused by their own software bugs, DOS attacks and other issues.
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