> > Have you looked at the tmpfs filesystem that has been added to 2.4? > > > > Very very very much faster than ext2 and ext3... > > Is it faster then the cache used for ext2 and ext3? Cos I seriously > doubt it... at least not so much faster that you'd bother with it for > the sole purpose of speed. And I think it can be swapped out so if you > leave something there long term, you're still hitting disk. > > The only reason I'd bother with it as a replacement for /tmp is if I had > tons of ram+swap and didn't use it all. Then it'd save me oh... > 128M-256M of disk space. ;) > > (Unless I'm wrong about tmpfs speed vs cache speed :) That only holds true if you measure only the speed of the actual writing and reading from /tmp. But the effect on your overall *system* speed is significant- because all of the writes eventually get scheduled, and many of the reads, too, adding to the overall busyness of the hard drive. With tmpfs, (assuming you have enough RAM that swappping is generally many megs away, yes), the writes are not done at all. Certainly it will hit the disk for swapping in a much more leisurely way than it will sync ext2 or ext3, so even if you don't have lots of RAM, it should still be easier on the overall disk thrashing. But I am speaking as someone with 512MB of RAM on all of the machines I use tmpfs on. For sure I wouldn't want to be journalling /tmp... it isn't called "/tmp" for nothing... -Tom
