Comment 8 for bug 571972

On 24 May 2010, at 4:08 am, Phil Kaslo wrote:

>
> We had been using amd instead of autofs on a large server, with possibly 100 - 200 concurrent login sessions.
> With autofs, each home directory for a logged in user would be a separate mount point. We found that things
> started to get ugly, when the number of mount points grew to a number somewhat less than 256, maybe 200
> to 220. Using instead static mounts from the file servers, and then using amd to manage symlinks, via map
> entries for /home of the form
> username fs:=/directory/path;type:=link
> keeps the number of nfs mounts down to the number of static mounts.
>
> We have been using autofs on all our other linux boxes (Ubuntu and Fedora). But due to this issue
> we had been using amd on our main instructional server, now running Ubuntu.
>
> Have other people had success with using autofs for /home, with large numbers of concurrent logins?
> With more than say 256 nfs mount points?

We avoided the issue by having users home directories being say, /home/t/tjrc, with the automount and the t level so there are only 26 mountpoints, regardless of the number of logins.

We saw a similar thing to you with our automounted /software directory, and used a similar solution to you; we statically mounted the fileserver elsewhere, and used autofs to manage symlinks to it. This was not due to number of filesystems mounted, but more because it copes better when the number of simultaneous mount requests gets large (such as when we reboot the entire 500 node compute cluster)

Tim