July 2010
3 posts
MongoDB
There are lots of MongoDB-related posts everywhere lately. Here are three important things you should know before delving into MongoDB:
MongoDB uses memory-mapped files for disk I/O. On 32-bit systems, you’ll quickly exceed the process size limit (4GB). So you should always run MongoDB in 64-bit in production.
MongoDB does not have single-node durability yet (they’re reportedly...
Getting memprof to work on Snow Leopard
memprof is a memory-profiler for Ruby (specifically MRI). It’s great for performance analysis, debugging memory leak issues, etc. But unfortunately it doesn’t work with the default Ruby that ships with Snow Leopard since there are no debug symbols installed. There are a few other restrictions at this point - memprof actually rewrites x86 binary in memory which is why it’s...
Wikipedia - Write amplification & TRIM command on... →
Also good reads: benchmarking SSD performance on Windows 7 and OS X with and without TRIM.
Earlier versions of Windows (pre-Windows 7) don’t have TRIM support apparently. The article doesn’t seem to have a good explanation for why performance in OS X doesn’t degrade due to write amplification even though TRIM hasn’t been set (at least according to the System Profiler app...