Fastest Linux filesystem for /tmp?

What's the fastest filesystem (and/or filesystem options) for a drive where I don't care about whether the data survives a crash or power-off, such as /tmp?

The data is a few hundred gigabytes so won't all fit in RAM. There is a mix of small and very large files (think HTML files and videos).

Is it best to just create a massive swap partition and use tmpfs? (Will that even work?) Or should I use ext2/3/4 or XFS or Btrfs? What are the optimization options I should use to turn off all the safety features and get the most performance out of the filesystem?

The disk is a HDD. An SSD is not feasible: This is a build server, so data is always being deleted and recreated, so the number of bytes written per day is a few times larger than the disk size. That means a consumer SSD is unlikely to last, and datacenter class SSDs designed for the high write load are too expensive.

Solution 1:

Sounds like your builds are rather large, so I'd stay away from massive swap + tmpfs - this could indiscriminately force your system into swapping while building which will ruin your build performance.

For my build systems I only had the ext2 and ext3 options, ext2 was faster (understandably - no journaling).

Look also at tune2fs and mount options in addition to mkfs options (as applicable). You could probably drop stuff like user_xattr, acl. You might be able to drop timestamping (noatime, nodiratime) but with care - some builds may depend on that.

Don't forget fragmentation, it really creeps up in such highly-churned partitions, especially if they often go over 80-90% fill level. I was re-formatting the build partitions about once a month - for my builds that alone meant some 10-15% improvement.

IMHO the best way of approaching this is to really try your options out, measure and compare using one of your typical builds as reference.

Side note: the speed of the HDD might not be the significant limiting factor in the overall build speed (I had builds which had less than 10% improvement in tmpfs/ramfs vs on HDDs). The build structure/dependencies/parallelism (which may change in time as the code evolves), -j factor, CPU/RAM load, networking, other infrastructure services your build might use can also matter significantly.