Rails and Scaling with Multiple Databases
It’s not Rails’s problem.
Introducing Rails Metal
David Heinemeier Hansson: “Rails Edge adopted Rack a while back and we’ve been exploring ways to expose that better. The first thing we did was to make it really easy to hook up any piece of Rack middleware in front of a Rails request. In your config/environment.rb file, you can do: config.middlewares.use(Rack::Cache, :verbose => true)”
Oh hell yes.
ncache
An Nginx module that acts as a gateway cache. I haven’t tried it yet but it’s a really good idea.
Ezra's "Merb, Rubinius and the Engine Yard Stack" Google Tech Talk
So I've been skeptical about Merb but I really like the world-view Ezra puts forth here: core framework code should be simple (no/little meta-programming), fast is good, Rack is awesome, etc.
Varnish's ESI Support
“Varnish implementes a subset of the ESI Language 1.0 defined by W3C, this document lays out some of the thoughts and rationale for choices made and advice for usage of these features.”
This lets you perform includes at the cache layer so that each included resource can have its own caching policy. Akamai edge proxies have supported this for some time, apparently.
The C10K problem
Dan Kegel: “You can buy a 1000MHz machine with 2 gigabytes of RAM and an 1000Mbit/sec Ethernet card for $1200 or so. Let’s see – at 20000 clients, that’s 50KHz, 100Kbytes, and 50Kbits/sec per client. It shouldn’t take any more horsepower than that to take four kilobytes from the disk and send them to the network once a second for each of twenty thousand clients. (That works out to $0.08 per client, by the way. Those $100/client licensing fees some operating systems charge are starting to look a little heavy!) So hardware is no longer the bottleneck. ”
Looks like this is from 2003 but is still pretty accurate as far as I can tell.
OO C is passable
Yossi Kreinin: “But I miss virtual functions. I really do. I sincerely think that each and every notable feature C++ adds to C makes the language worse, with the single exception of virtual functions.”
Why aren’t you using ionice yet???
I'm more than a little embarased that I've never heard of this utility. I think most modern kernels prioritize IO with normal nice, though…
valgrind and ruby
Evan Weaver: “These leaks tend to grow slowly. Your Rails app definitely has this kind of leak, especially if it uses the ActiveRecord session store.”