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Strange NFS problem over WAN

jerry1
Super Advisor

Strange NFS problem over WAN

When trying to read a line from a test file
and writing a line out to a file over WAN
over NFS, data lines are missing. If I run it
on our local network over NFS it works fine.

Input data file.

1 a
2 b
3 c
4 d
5 e
6 f
7 g
8 h
9 i
10 j

Output data file to NFS mount.
It should be the same as above but basically every other line is missing:

1 a
3 c
5 e
7 g
9 i
10 j


Script used:

#!/bin/ksh

OUTFILE=$1.new
rm -f $OUTFILE 2> /dev/null

while read line
do
print - "$line" >> $OUTFILE
done < $1
6 REPLIES
Dave Olker
HPE Pro

Re: Strange NFS problem over WAN

What NFS mount options are you using for the WAN filesystem?

# nfsstat -m

Dave
jerry1
Super Advisor

Re: Strange NFS problem over WAN

/a from appsvr2:/a
Flags: vers=3,proto=tcp,sec=sys,hard,intr,link,symlink,acl,rsize=32768,wsize=
32768,retrans=5
Dave Olker
HPE Pro

Re: Strange NFS problem over WAN

I'm curious if this is a caching issue. You might want to try disabling the caches on the client just to see if the problem clears up. You can do this by mounting the filesystem with the "noac" mount option.

Regards,

Dave
jerry1
Super Advisor

Re: Strange NFS problem over WAN

The noac option worked. Why?
And how can I make this global for all
automounts on the clients?

Dave Olker
HPE Pro

Re: Strange NFS problem over WAN

If disabling the client-side caches fixed the problem then I'm gonna go way out on a limb and guess the problem is due to caching on the client. :)

You can add the "noac" option to any AutoFS map entry just like any other mount option. However, I'd discourage you from using "noac" globally throughout your environment because disabling caching can negatively affect performance. I would only use this option on the filesystem exhibiting the behavior you're trying to resolve.

Regards,

Dave
jerry1
Super Advisor

Re: Strange NFS problem over WAN

Well, the problem is any host moved to
the other site accessing any nfs over the
wan.
I do not understand why the wan would be
affecting nfs. If they were nis bound over
at the other site, I could just change
the one map. But I have to change all the
local auto maps on all the systems that
have rw for that nfs mount so they can
write to it without corruption to their
output files.