Pulp

libeatmydata (debian family) / nosync (RH family) are LD_PRELOAD libraries that improve system disk write performance by squashing sync/fsync function calls. Thus all disk writes are cached in RAM and written to disk leisurely. They are ideal for any sort of temporary environment, like test and image building.

They are pointless when a VM's hypervisor has its virtual hard disk configured to squash sync/fsync functional calls (libvirt/kvm: "unsafe" or "writeback"), but it is unclear whether Travis does that or not with its VMs.
(Also, Travis has switched hypervisors in the past and old guidelines may no longer apply.)

We should run a test of whether Travis will benefit from libeatmydata. If it does, then methodically integrate it into tasks running directly on Travis, the containers, etc.