Double nfs mount not showing up

[Simon]

Hi There,

We have three debian lenny boxes..

A (ftp server)
B (web server)
C (storage server)

The web server has a drive for /www/... within /www/ there are a
couple of nfs mounts to the storage server
(/www/www.site.com/nfs_to_storage_server/). Within that directory
there are files :)

Now, the ftp server mounts the web servers /www/ drive as nfs, but it
cannot see the files in the directories that are on the mounted
folders (/www/www.site.com/nfs_to_storage_server/).

Long winded... but i cant figure out any other way to describe it :D

Any ideas why the ftp server cant see the files on the storage server
mounts on the web server? (phew)

Thanks

Simon

_______________________________________________
NZLUG mailing list ***@linux.net.nz
http://www.linux.net.nz/cgi-bin/mailman/listinfo/nzlug

[Daniel Pittman]

Post by Simon
We have three debian lenny boxes..
A (ftp server)
B (web server)
C (storage server)
The web server has a drive for /www/... within /www/ there are a
couple of nfs mounts to the storage server
(/www/www.site.com/nfs_to_storage_server/). Within that directory
there are files :)
Now, the ftp server mounts the web servers /www/ drive as nfs, but it
cannot see the files in the directories that are on the mounted
folders (/www/www.site.com/nfs_to_storage_server/).
Long winded... but i cant figure out any other way to describe it :D
Any ideas why the ftp server cant see the files on the storage server
mounts on the web server? (phew)

I didn't think that NFS mounts were exportable over NFS, although I am not
certain. However, a quick test to check would be to create a file in the
underlying directory *below* the mount and see if it showed up.

Daniel

In any case you *really* don't want to have that double layer of mounts,
because it is an invitation to the "lose my data" fairy to visit. Just mount
the same directory on the storage server on both other machines.

[Daniel Lawson]

Post by Simon
We have three debian lenny boxes..
A (ftp server)
B (web server)
C (storage server)
The web server has a drive for /www/... within /www/ there are a
couple of nfs mounts to the storage server
(/www/www.site.com/nfs_to_storage_server/). Within that directory
there are files :)
Now, the ftp server mounts the web servers /www/ drive as nfs, but it
cannot see the files in the directories that are on the mounted
folders (/www/www.site.com/nfs_to_storage_server/).
Long winded... but i cant figure out any other way to describe it :D
Any ideas why the ftp server cant see the files on the storage server
mounts on the web server? (phew)

NFS isn't allowing you to re-export your C-B NFS mount from B-A. This is
generally considered to be a security feature: Say host A doesn't have
any kind of permission to access host C. Re-exporting the host C NFS
from host B to host A will bypass that, and host B has no way of
understanding whether or not host A has permission to talk to host C.

A quick google search suggests that the user-space NFS server
implementation may allow it, but also that the general consensus is
that host A should mount the shares from host C directly.

If you're interested in looking further, the term you want to search for
is 're-export' or something along those lines.





_______________________________________________
NZLUG mailing list ***@linux.net.nz
http://www.linux.net.nz/cgi-bin/mailman/listinfo/nzlug

[Simon]

If you're interested in looking further, the term you want to search for is
're-export' or something along those lines.

Thanks for the great reply Daniel, the term made it easy to research.
After taking a good look at things, i'm going to NOT do this and have
sorted a different sharing setup so that we dont have to re-export.

Many thanks

Simon

_______________________________________________
NZLUG mailing list ***@linux.net.nz
http://www.linux.net.nz/cgi-bin/mailman/listinfo/nzlug