While attending OSCON 2009 w/ my faithful sidekick fluffy, we constantly kept finding instances of a common theme. The leading companies and projects seem to share one attribute that might shock you.
They all have at least *some* crappy code. At some point, all of them › Continue reading
It semeed so simple, just setup two memcachedb instances and point them at eachother. Instant fault tolerance, Right? If only it were so simple!
Its not entirely clear from the documentation how to setup memcachedb for fault tolerance. Here’s the procedures I’ve found useful.
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So a few days ago, my big mean MySQL server started having problems that were very hard to explain. It was slowing down, taking a minute to run queries that usually take a few seconds, and Linux load averages were in the teens, despite having quiet disks (less than 0.1% cpu IO wait time) and plenty of RAM (128G for about 200G of data total…).
The developers were stumped. The other systems guys were stumped. So was I. But it still seemed ok. We found all sorts of things to point fingers at, but nothing made sense.
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Anybody who is in IT in America, has probably experienced that sinking feeling when somebody somehow introduces the latest version of Microsoft Office into their organization. It usually comes in like some corporate ninja while you’re not looking. Whether its an application that your accounting department writes with the new version of Access, or that Outlook plugin that somebody locked in to, you have to deal with it.
The most frustrating part of this for me is never that people are going to use Office. Its not a bad product. Whats frustrating, is that every 3 or 4 years, Microsoft somehow gets people to pay $300-$400 per user. › Continue reading
Just a few weeks ago, I found out that thread_concurrency’s purported magical effects at correcting MySQL’s concurrency limitations (especially in 4.1) were something of a myth. It was a post on mysql’s lists that alerted me to this. Apparently it only works on Solaris, Linux’s threading library ignores this parameter completely. This is not to be confused with innodb_thread_concurrency, which is quite useful in controlling the flow of transactions through InnoDB. I think the problem really lies in the fact that the default my.cnf example configs tell us to set thread_concurrency to the number of CPU’s*2. They fail to mention that this only matters on Solaris, though the manual is quite clear.
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