I have a program that is very heavily hitting the file system, reading and writing randomly to a set of working files. The files total several gigabytes in size, but I can spare the RAM to keep them all mostly in memory. The machines this program runs on are typically Ubuntu Linux boxes.

Is there a way to configure the file system to have a very very large cache, and even to cache writes so they hit the disk later? I understand the issues with power loss or such, and am prepared to accept that. Crashing aside, in normal operation the writes should eventually reach the disk!

Or is there a way to create a RAM disk that writes-through to real disk?