[CentOS] how does autofs deal with stuck NFS mounts and suspending to RAM?

Mon May 18 23:36:03 UTC 2020
Warren Young <warren at etr-usa.com>

On May 18, 2020, at 5:13 AM, hw <hw at gc-24.de> wrote:
> Is there a better alternative for mounting remote file systems over unreliable 
> connections?

I don’t have a good answer for you, because if you’d asked me without all this backstory whether NFS or SSHFS is more tolerant of bad connections, I’d have told you SSHFS.

NFS comes out of the "Unix lab” world, where all of the computers are hard-wired to nearby servers.  It gets really annoyed when packet loss starts happening, and since it’s down in the kernel, that can mean the whole box locks up until NFS gets happy again.

NFS is that way on purpose: it’s often used to provide critical file service (e.g. root-on-NFS) so if file I/O stops happening it *must* block and wait out the failure, else all I/O dependent on NFS starts failing.

Some of this affects SSHFS as well.  To some extent, the solution to the broader problem is “Dropbox” et al.  That is, a solution that was designed around the idea that connectivity might not be constant.

This is also while DVCSes like Git have become popular.