topic Re: Multiple Identical NFS mounts of same filesystem in Operating System - HP-UX

Multiple Identical NFS mounts of same filesystem

Stephen Stephanian — Thu, 15 Dec 2005 11:25:13 GMT

In looking at list of mounted filesystems, I'm seeing the same NFS filesystems mounted to the same mount point multiple times, eg:

servera:/appl/data/fs1 mounted as /appl/data/fs1 - in one case, 28 times. fstab entry shows one "mount" for this system, ro, soft.

Any ideas why this is happening, and is it a bad thing? Running HPUX 11.11; Looking at /etc/rc.config.d/nfsconf, also note that we're NOT using AutoFS, but old automount.

Re: Multiple Identical NFS mounts of same filesystem

Dave Olker — Thu, 15 Dec 2005 11:34:38 GMT

Hi Steve,

That should not be happening and the only reason I can imagine would be a bug in HP-UX to allow it. Once a filesystem is mounted at the VFS (Virtual File System) layer, there should not be a way for another filesystem to occupy the same area of the VFS.

At this point it's not clear if this is one filesystem being represented 28 times or 28 separate filesystems. In either case it's bad.

One suggestion that I make to every HP-UX customer running the old legacy automounter is to migrate to AutoFS. Since you're running 11.11, you can download the Enhanced AutoFS product from the Software Depot site: http://software.hp.com. This is a vastly improved automounter than the legacy one you're using. You can still do all the same things the dinosaur old automounter can do but it has the benefit of a much newer source code base, a much more supportable implementation, thousands of fewer bugs, etc.

My recommendation would be to install the Enhanced AutoFS product and see if that resolves your problem.

Regards,

Dave

Re: Multiple Identical NFS mounts of same filesystem

Patrick Wallek — Thu, 15 Dec 2005 11:42:26 GMT

How are you looking at the list of mounted filesystems?

Re: Multiple Identical NFS mounts of same filesystem

Stephen Stephanian — Thu, 15 Dec 2005 12:07:12 GMT

Thanks for the quick response....and looking further, sorry for any confusion.

Patrick, I'm actually using a script you modified that I got here at the forum; (bdfmegs? I think I renamed it) looking a little further, now, perhaps there's a bug? df -k with grep for filesystem comes up with 1 line; ditto cat/grep of /etc/mnttab. I have many NFS mounts, most show up multiple times in output but not consistently same number, most 1 - 4 times.

Dave, I have your book "Optimizing NFS performance", which led me down the automount/autofs path; will definitely look into changing over; thanks.

Re: Multiple Identical NFS mounts of same filesystem

Patrick Wallek — Thu, 15 Dec 2005 12:10:30 GMT

Ahh....Yes, there is a bug in that script. It has definite issues when dealing with NFS mounts. That script was originally posted by Bill Hassell, I believe. I remember a post from a few weeks ago where someone else spotted that bug and Bill is aware of it. I am not sure if it is fixed or not.

Re: Multiple Identical NFS mounts of same filesystem

Patrick Wallek — Thu, 15 Dec 2005 12:50:15 GMT

Attached is a modified version of bdfmegs that I just modified to fix the NFS mount issue.

Re: Multiple Identical NFS mounts of same filesystem

Patrick Wallek — Thu, 15 Dec 2005 12:51:08 GMT

Attached here is the fixed version that I modified to display the output in GB instead of MB.

Re: Multiple Identical NFS mounts of same filesystem

Stephen Stephanian — Thu, 15 Dec 2005 13:24:53 GMT

Thank you!

Re: Multiple Identical NFS mounts of same filesystem

Stephen Stephanian — Thu, 15 Dec 2005 13:38:00 GMT

Revised script fixes problem; AutoFS question answered.