> In a message dated: Thu, 20 Dec 2001 12:30:00 PST
> "Taylor, ForrestX" said:
> 
> >Oh, I thought that you were using the auto.net script to 
> automount using
> >machine names.  What exactly are you doing, and which OS are 
> you using?
> 
> No, we're not doing that.
> 
> We're using Linux, depending upon the server, it's either 2.2.20, 
> 2.4.14, or 2.4.16.  But right now that's sort of irrellevent, since 
> all I'm looking for is documentation which explains how the symlink 
> feature works and how to disable it.  Where is the nosymlink option 
> mentioned.  I've looked in man pages for mount, nfs, autofs, 
> and automount, but haven't seen any mention of 'nosymlink' anywhere.
> Is this an undocumented feature? 


I don't think that it is documented anywhere (Jeremy?).

 
> Anyway, what we're doing is this.  We have an nfs server which 
> exports a bunch of file systems to the world.  All desktop clients 
> mount the file systems via automount.  So, though on the server we 
> have file system names like /home1, /home2, /home3, etc. the desktops 
> all only see /homes and everyone's homedir "automagically" appears 
> mounted on /homes/<username>.
> 
> We also run autofs on the NFS server itself so that when people log 
> into the system directly, they have the same view of things as they 
> do on their desktop systems.  They usually log into this system 
> directly to do things like large software compilations which would 
> otherwise saturate the network if done via NFS (or so they say:)
> 
> When on the NFS server though, autofs creates a symlink from say,
> /homes to /home1/pll, so if I do a df I see:
> 
>       $ pwd
>       /homes/pll
>       $ df .
>       Filesystem           1k-blocks      Used Available Use% 
> Mounted on
>       /dev/sda1             26209780  25313816    629688  98% /home1


So, does it create a symlink /homes pointing to /home1, or a /homes/pl1
pointing to /home1/pl1?

 
> vs. what I see on my desktop:
> 
>       $ pwd 
>       /homes/pll
>       $ df .
>       Filesystem           1k-blocks      Used Available Use% 
> Mounted on
>       zaphod:/home1/pll     26209780  25319552    623952  98% 
> /homes/pll
> 
> What I want to do is get the NFS server (zaphod in this case) to 
> appear exactly as if I'm on my desktop.  IOW, I want the NFS server 
> to truly NFS mount it's own file systems.


Like HPA mentioned, you need 2.4 kernels to do this.


> 
> I know this probably sounds crazy, but there's good reason for doing 
> this.  We're trying to figure out how to handle a clustered NFS 
> server environment.  Currently if one logs into an NFS server which 
> is clustered *and* is running autofs, they end up in the directory 
> structure of the actual file system.  If the cluster needs to fail 
> over for what ever reason, either, you need to implement the cluster 
> with a 'forced unmount' capability, or, you need to have the file 
> systems actually be NFS mounted elsewhere other than on the real, 
> local mount point.
> 
> The 'forced unmount' option is ugly, since it will violently kill all 
> processes which are preventing that file system from being unmounted, 
> which could result in the user in question losing data.  
> Unfortunately with the symlink optimization turned on, this is what 
> we have to resort to.  Or, we could manually nfs mount all local 
> file systems to a second mount point via the fstab file.
> 
> This second option is ugly, because it error prone, it forces all 
> file systems to always be mounted twice, and it requires manual 
> upkeep in 3 locations (2 /etc/fstabs + automount maps)
> 
> If we could turn of symlink optimizations and have the NFS server NFS 
> mount it's own file systems on demand to another location, we can get 
> the NFS server to fail over without the user ever noticing.  This is 
> currently exactly what happens when a user is NFS mounting a file 
> system on to their desktop system from a clustered NFS server now.
> 
> Does that help clarify what we're trying to do?


Yes.
Here is the excerpt from auto.net:

# add "nosymlink" here if you want to suppress symlinking local filesystems
# add "nonstrict" to make it OK for some filesystems to not mount
opts="-fstype=nfs,hard,intr,nodev,nosuid"

I just tested your situation on my Red Hat 7.2 box.  I added an entry in
/etc/auto.misc:
test  -fstype=nfs  myhost:/home
and it seems to work.  No symlink, and it shows up in df (twice).  What does
the line in your auto.* file look like?

Forrest

> 
> Thanks,
> -- 
> 
> Seeya,
> Paul
> ----
> 
>                         God Bless America!
> 
>       ...we don't need to be perfect to be the best around,
>               and we never stop trying to be better. 
>                      Tom Clancy, The Bear and The Dragon
> 
> 

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