Ahh seems like a few people do take the time to read my blog:) Peter Z Commented here on my common disk performance mistakes post. He makes some great arguments, and you may want to give it a read. While he does not agree with everything I say it is interesting to see his views. Remember different folks have different experiences and a lot of times there are multiple roads on the path the performance nirvana.
Let me start off saying I wholly admit that saying “everything” is a disk issue is a dramatic exaggeration. And i did not specifically say disk, I said “The problem is always an IO problem”, more on that later. I have run into my far share of issues outside of this sphere ( network, context switching, cpu ), but I still find disk performance to be by far the most common issue effecting systems I deal with. In my opinion It is the reason memcache had to be invented, the reason for explosive growth in the amount of memory in servers, etc. If all of your disks performed even at half the speed of memory the urgent need to fit everything into memory would not be so urgent ( Now that sounds silly ). This is not a MySQL specific issue either I was dealing with disk performance issues since the mid 90’s in other database systems.



