title: Can large files stored on AWS EFS be appended to without retransmitting the entire file?
body: <p>I looked into s3fs for holding some data files from a legacy ec2/fargate application and the conclusion that I came to is that it's not suitable in a use case where you are regularly appending to a file, because the entire file gets retransmitted.  This lead me to choose EFS. Then I read that EFS mounts as an NFS share, and now I'm wondering if EFS has that same drawback.</p>
  <p>From searching for information on NFS itself I have not found an explicit yes or no about this, but I have found several academic papers making experimental forks of NFS that attempt to either enable or improve &quot;appending&quot;.  Which vaguely leads me to believe NFS by itself is NOT practical for appending to remote files.  But then again, most of the papers are atleast 5 if not 10 or 15 years old, so NFS could have incorporated the functionality proposed in these papers, or AWS could even be running a version of the NFS protocol as proposed in these papers.  Basically, it's hard to find an answer for NFS and even then, unclear how well that answer carries over to EFS.</p>
  <p>If you have a big file on an EFS volume/share, is it efficient to append to it or does it that force a remote rewrite of the whole file each time?</p>