Let's see if I can make your day with a shameless plug. First of all, using the kernel's paging algorithm for a database is awful. It has way less information

Let's see if I can make your day with a shameless plug. First of all, using the kernel's paging algorithm for a database is awful. It has way less information about your access patterns than the database, so it's going to make a lot of bad decisions, and a bunch of MongoDB's problems with fragmentation and performance cliffs come from using mmap. It's quick and dirty. Here's the alternative, and it supports the exact same document storage as MongoDB, the same administration interface, actually the same protocol everywhere, hot backup, and however many nodes you want: TokuMX[1]. It does all those things because it's actually mostly MongoDB, just with the storage engine replaced with an engine that works faster, compresses your data, and has more mature things like document-level locking for writers and better multi-document isolation semantics on a single node. Give it a whirl and let us know if you like it. [1]: http://www.tokutek.com/products/tokumx-for-mongodb http://www.tokutek.com/products/tokumx-for-mongodb