Would jumbo frames cause server disconnection if there are no errors incremented on the interface?

[ronjonjonjon1]

I have an Oracle DBA that is trying to connect to an App Server via an ESXi.  When he connects to it to do his work, it will lose connection after about 10-30 minutes and he will lose his data.

This is the physical connection:

ESXi>>>>>>Cisco UCS>>>>>>>>Nexus 5K>>>>>>>NetApp(Where the App Server lives)

I noticed in the configuration of the 5K, that there were jumbo frames on the interfaces and port-channels that connect to the App Server.  There were no errors or any other increments on the input-output packet section of the interfaces.  Also, the MTU is configured as 1500 for all interfaces which was verified.  Sorry, can't post config b/c gov. environment.

So, would the jumbo frames be a cause for disconnection, since its not configured to 'mtu 9216'?  Also, if this might be the problem, MTU size would have to be configured on the interface, port-channel, and interface VLAN correct?

[Reza Sharifi]

I noticed in the configuration of the 5K, that there were jumbo frames on the interfaces and port-channels that connect to the App Server.  There were no errors or any other increments on the input-output packet section of the interfaces.  Also, the MTU is configured as 1500 for all interfaces which was verified.  Sorry, can't post config b/c gov. environment.

It is very common and recommended by storage vendors to turn on the jumbo frames when connecting to storage heads. On the Nexus 5k, this configuration is global and applies to the whole switch. Enabling it should not cause any interface disconnect. To check to make sure you have the correct MTU setup, use "show que inter x.x"

Also, check "sh run" to make sure you have the correct jumbo frame policy in place.

HTH

[ronjonjonjon1]

Thanks for answering. I did read that about it already being enabled,but I could've swore I just saw the default 1500 on at least the interfaces. I didn't show int on the port channels or the int vlans. 

[Reza Sharifi]

Use the show commands for physical interfaces:

Example:

show queu interface ex/x

or

show queu interface ex/x details

HTH

[MHM Cisco World]

https://community.cisco.com/t5/data-center-documents/configuring-jumbo-mtu-support-on-nexus-7000-and-5000/ta-p/3149184

See above