Long NFS mount delays on RHEL 7.6

[bsnyder27]

Our environment had a new issue introduced with servers we've upgraded from RHEL 7.5 to RHEL 7.6.

IF the server meets the condition where there are no current NFS mounts to our FAS, the following delays occur on a RHEL 7.6 system:

1. 45 second delay when mounting a share that is NFS 4.0/4.1 with sec=sys to NetApp FAS
2. 90 second delay when mounting a share that is NFS 4.0/4.1 with sec=krb5,krb5i,krb5p NetApp FAS
3. No effect on NFS 3 mounts for anything
4. No delay on RHEL 7.5 or RHEL 6.10 for the NetApp
5. 7'30" delay when mounting a share from a synology system we run and the same to a hosted share that I'm not sure of the back-end - RHEL 7.6 
6. No delay mounting the Synology share from a RHEL 7.5 or RHEL 6.10 host
7. 6"/12" delay for the hosted share from 7.5 host and no delay from the RHEL 6.10 host

Can be reproduced on 7.6 servers, but doesn't occur with 7.5 or our 6.x servers.

Anyone else able to reproduce such behavior?

[Vijay_ramamurthy]

Hi ,

If we take a simultaneous packet trace from NetApp and RHEL client reproducing the good and bad scenario, we can find what is the reason for the delay  seen with different client versions. 

Since ONTAP code is same but with different client versions we notice different delays, this looks to be some change in the client which could be causing this. 

I would suggest to open a ticket so that support can look at the packet traces , compare  and provide an analysis.  

[bsnyder27]

I agree with it being a change on the client. I've started by engaging Red Hat but will certainly engage NetApp support if they provide me no help with this.

[Vijay_ramamurthy]

Hi ,

Sure. Please open a support ticket with us and we can provide more details after reviewing the trace on where the delay is coming from. 

Thanks

Vijay