title: Git fetch for many files is slow against a high-latency disk
body: <p>What I'm interested in here is some insight into git's internals - </p>
  
  <p>If I have a repo hosted remotely on Bitbucket with many files (say ~25000, they're all around 2K in size), why is the first fetch so slow when targeting a high-latency disk?</p>
  
  <p>I would expect operations like the first checkout to be slow, due to the need to write lots of files, but the fetch should only be receiving a handful of metadata and pack files and writing those to disk. The disk is high-latency but throughput is fine, so the performance of writing a small number of large files is generally fine.</p>