renaming NFS servers

renaming NFS servers

Post by Dan Strombe » Sat, 24 Mar 2001 02:44:53



If we rename an NFS server, but keeps its IP address the same, what
will happen on the client machines?

That is, will existing NFS mounts continue to work until a reboot, at
which point /etc/vfstab and such will have to have been updated?

Would it be possible to have two names, say two A's or a CNAME for the
NFS server to make the migration easier?  My guess is in old solaris,
this would work, but in contemporary solaris it would not.
--
Dan Stromberg                                               UCI/NACS/DCS

 
 
 

renaming NFS servers

Post by Barry Margoli » Sat, 24 Mar 2001 03:04:20




>If we rename an NFS server, but keeps its IP address the same, what
>will happen on the client machines?

>That is, will existing NFS mounts continue to work until a reboot, at
>which point /etc/vfstab and such will have to have been updated?

Yes.  Hostnames are resolved to IP addresses at mount time, and from then
on it just uses the IP address.

Quote:>Would it be possible to have two names, say two A's or a CNAME for the
>NFS server to make the migration easier?  My guess is in old solaris,
>this would work, but in contemporary solaris it would not.

I don't see why it shouldn't work in any version of Solaris.  It doesn't
matter how the name is translated to an address.

--

Genuity, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.

 
 
 

renaming NFS servers

Post by Steve Bellen » Sat, 24 Mar 2001 04:26:23


The correct way to do this is
1. Make the new name an alias for the old name
<---can do stuff here with both old or new name-->
2. Swap rolls make the machine have the new name and the old name
is made an alias
<---can do stuff here with both old or new name-->
3. Make sure there is not use of the old name on any of the clients.
4. Remove old name. (optional).

Since #3 is so hard to be sure of, one often finds the old name
as an alias long after there is any reason for it, #4 never gets
done.



>If we rename an NFS server, but keeps its IP address the same, what
>will happen on the client machines?

>That is, will existing NFS mounts continue to work until a reboot, at
>which point /etc/vfstab and such will have to have been updated?

>Would it be possible to have two names, say two A's or a CNAME for the
>NFS server to make the migration easier?  My guess is in old solaris,
>this would work, but in contemporary solaris it would not.
>--
>Dan Stromberg                                               UCI/NACS/DCS

--
http://www.math.fsu.edu/~bellenot
bellenot <At/> math.fsu.edu
+1.850.644.7189 (4053fax)
 
 
 

renaming NFS servers

Post by Dan Strombe » Sat, 24 Mar 2001 04:32:39





<>If we rename an NFS server, but keeps its IP address the same, what
<>will happen on the client machines?
<>
<>That is, will existing NFS mounts continue to work until a reboot, at
<>which point /etc/vfstab and such will have to have been updated?
<
<Yes.  Hostnames are resolved to IP addresses at mount time, and from then
<on it just uses the IP address.
<
<>Would it be possible to have two names, say two A's or a CNAME for the
<>NFS server to make the migration easier?  My guess is in old solaris,
<>this would work, but in contemporary solaris it would not.
<
<I don't see why it shouldn't work in any version of Solaris.  It doesn't
<matter how the name is translated to an address.

We've had difficulty exporting to an alias with recent Solaris - both
CNAME's and a second A record for the same IP seemed to have problems.
We actually seemed to have to use the same name as what the PTR points
to get our NFS mounts to work.

Thanks for the response.

Can someone second Barry's belief before I run off and do some testing
to see how we got the wrong idea a while back?
--
Dan Stromberg                                               UCI/NACS/DCS

 
 
 

renaming NFS servers

Post by Barry Margoli » Sat, 24 Mar 2001 04:42:52




>We've had difficulty exporting to an alias with recent Solaris - both
>CNAME's and a second A record for the same IP seemed to have problems.
>We actually seemed to have to use the same name as what the PTR points
>to get our NFS mounts to work.

Exporting is different from mounting.  In the case of exporting, when a
mount request comes in, the server translates the client's address to a
name, and then looks it up in the export list.  So the PTR record has to
point to the name in the export list.

When you mount, you start off with a name, and translate it to an address
so you can make the connection.  You're not checking an incoming packet, so
no address->name translation is necessary.

--

Genuity, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.

 
 
 

renaming NFS servers

Post by Casper H.S. Dik - Network Security Engine » Sat, 24 Mar 2001 04:35:51


[[ PLEASE DON'T SEND ME EMAIL COPIES OF POSTINGS ]]


>If we rename an NFS server, but keeps its IP address the same, what
>will happen on the client machines?

Nothing.

Quote:>That is, will existing NFS mounts continue to work until a reboot, at
>which point /etc/vfstab and such will have to have been updated?

Yes.

Quote:>Would it be possible to have two names, say two A's or a CNAME for the
>NFS server to make the migration easier?  My guess is in old solaris,
>this would work, but in contemporary solaris it would not.

That would work too.

Why wouldn't that work?

Statd may have a problem reclaiming locks as it keeps track of server
names when there are outstanding locks.

Casper
--
Expressed in this posting are my opinions.  They are in no way related
to opinions held by my employer, Sun Microsystems.
Statements on Sun products included here are not gospel and may
be fiction rather than truth.

 
 
 

renaming NFS servers

Post by Dan Strombe » Sat, 24 Mar 2001 05:28:42





<>We've had difficulty exporting to an alias with recent Solaris - both
<>CNAME's and a second A record for the same IP seemed to have problems.
<>We actually seemed to have to use the same name as what the PTR points
<>to get our NFS mounts to work.
<
<Exporting is different from mounting.  In the case of exporting, when a
<mount request comes in, the server translates the client's address to a
<name, and then looks it up in the export list.  So the PTR record has to
<point to the name in the export list.

This seems obvious in retrospect.  Thanks.

--
Dan Stromberg                                               UCI/NACS/DCS

 
 
 

renaming NFS servers

Post by Dan Strombe » Sat, 24 Mar 2001 05:39:05




<[[ PLEASE DON'T SEND ME EMAIL COPIES OF POSTINGS ]]
<
<>Would it be possible to have two names, say two A's or a CNAME for the
<>NFS server to make the migration easier?  My guess is in old solaris,
<>this would work, but in contemporary solaris it would not.
<
<That would work too.
<
<
<Why wouldn't that work?

As Barry pointed out, I was mixing up exporting and mounting.

<Statd may have a problem reclaiming locks as it keeps track of server
<names when there are outstanding locks.

This might be an issue for us, though probably not a huge one.

EG, we have netscape in one of the filesystems on the server to be
renamed, and IIRC, netscape likes to lock one of its files - perhaps
it was the spelling dictionary or something.  When we had locking
problems on our NFS server, netscape would hang sometimes.  So when we
rename this NFS server, should anticipate that already-running
netscape processes will hang?

--
Dan Stromberg                                               UCI/NACS/DCS

 
 
 

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Anyone using a Unix box to provide NFS service to a large number of DOS machines?
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WordPerfect. The Unix box will not be loaded down.

                                    thanks,

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