topic Re: NFS mount requests going though the Virtual Interface in Operating System - HP-UX

NFS mount requests going though the Virtual Interface

Naveej.K.A — Wed, 06 Jun 2012 07:01:09 GMT

Scenario:-

An NFS Server, server exports an NFS filesystem called /ignitebkp to an NFS client, client. Share rw access & mount access are given to client only.

The client has a primary interface (lan26) and multiple virtual interfaces (Yes, service guard packages).

Problem:-

mount permission denied on client. On examining the mountd.log on server, I see that the requests to mount are coming from the virtual interface and not from the IP address of client. How can I get the client to send the request for mount and all future access through its primary interface which actually resolves to client in DNS?

Re: NFS mount requests going though the Virtual Interface

Dave Olker — Wed, 06 Jun 2012 07:33:26 GMT

Are you saying there are multiple IP interfaces on the same subnet? If not, this is a matter of selecting the proper NFS server IP address that routes through the appropriate client interface. If your NFS client has numerous IP interfaces on the same subnet, that gets a little trickier to force the client to send using a specific interface.

If you want the client to send mount requests using the primary IP address of the interface you can try experimenting with the kctune parameter ip_strong_es_model. A setting of 2 might give you the behavior you're looking for.

Dave

Re: NFS mount requests going though the Virtual Interface

Naveej.K.A — Wed, 06 Jun 2012 09:37:58 GMT

Hi Dave.

Thanks for your reply.

Yes, I have multiple interfaces (one physical & many virtual) which are on the same subnet. These virtual interfaces are my service guard package IP addresses.

From your reply, it looks like a common behavior. I would like to know who & what determines which IP address should send the mount request. Meanwhile, I will do some study on ip_strong_es_model and will test it.

But, I am curious to know if this random selection is a known behavior.

Regards,

Naveej

Re: NFS mount requests going though the Virtual Interface

Dave Olker — Wed, 06 Jun 2012 16:29:00 GMT

Naveej.K.A wrote:
But, I am curious to know if this random selection is a known behavior.

I very much doubt this is a "random" selection. More likely it is selecting the best interface to use based on the IP routing tables. You can verify this by examining the routing tables via "netstat -rn". You can also manipulate the routing tables to try to get the preferred interface used during NFS mounts, though I would first experiment with ip_strong_es_model.

Dave

Re: NFS mount requests going though the Virtual Interface

Naveej.K.A — Thu, 07 Jun 2012 03:58:47 GMT

Dave, Thanks for following up.

Well, I have a default gateway for the entire subnet. Both the physical & the virtual interface are on the same subnet, so I guess the routing information is not being used to pick up which interface the client must use.

To make it clear.

10.209.11.82   client       client.domain.com  ---> plumbed on lan26
10.209.11.89   client6      client6.domain.com ---> plumbed on lan26:4
 
10.209.11.16   server       server.domain.com

client & server resolve to the hostname in DNS. whereas, client6 is my package name. The request for mount is going from client6instead of client.

I can give access permission in my dfstab for client6, but the whole thing will break when my package moves from client toanotherclient.

Re: NFS mount requests going though the Virtual Interface

Rajesh K Chaurasia — Fri, 08 Jun 2012 06:28:24 GMT

Not sure if this HP-UX routing gray paper (NOT an official HP document) could be of some help in routing in multi-homed environments.

http://www.mayoxide.com/presentations/Understanding_hpux_routing.pdf

Regards

-Rajesh