topic Re: MTU config differ between filers in ONTAP Hardware

MTU config differ between filers

DHUCKSTEP — Thu, 05 Jun 2025 05:35:38 GMT

MTU setting between one our FAS3210 fires and its HA partner don't match. One filer has MTU defined in the /etc/hosts file, the other filer does not. Wondering if removing the defined entry to mimic the HA partner is a disruptive procedure or will the system accommodate that change without disruption.

Thanks in advance.

Re: MTU config differ between filers

JGPSHNTAP — Tue, 20 May 2014 11:52:39 GMT

MTU in the host file? Are you sure it's not the rc file?

Can you show us an example.

Re: MTU config differ between filers

DHUCKSTEP — Tue, 20 May 2014 16:45:51 GMT

Doh, I guess my notes were incorrect. Yes, rc file must be what I'm talking about.

Re: MTU config differ between filers

JGPSHNTAP — Tue, 20 May 2014 16:48:49 GMT

ifconfig -a will tell you what setting your MTU's are at.. If you don't specify it will default down to 1500, which is i'm sure what you are running.

Re: MTU config differ between filers

DHUCKSTEP — Tue, 20 May 2014 17:00:19 GMT

If I remove the mtu line from the rc file (on the filer that has the static entry) will the change be disruptive, i.e., require stack restart?

Re: MTU config differ between filers

JGPSHNTAP — Tue, 20 May 2014 17:02:30 GMT

You haven't answered my initial question, what is the MTU setting.. ifconfig -a of the interface

Re: MTU config differ between filers

DHUCKSTEP — Tue, 20 May 2014 17:04:33 GMT

Sorry, this is an HA pair. One doesn't have it defined in the rc file and is at 1500. The partner does have it statically set and it is at 1500. This became an issue when I ran an upgrade advisor and it was pointed out that the rc files don't match.

Re: MTU config differ between filers

DHUCKSTEP — Tue, 20 May 2014 17:07:25 GMT

This is the static entry for one filer -

ifconfig vif1 `hostname`-vif1 netmask 255.255.255.0 partner vif1 mtusize 1500 trusted -wins u

This is what's defined on the other filer -

ifconfig vif1 `hostname`-vif1 netmask 255.255.255.0 partner vif1 wins

Re: MTU config differ between filers

JGPSHNTAP — Tue, 20 May 2014 17:19:54 GMT

The reason I was asking b/c I wanted to make sure there were no jumbo frames.. Also you didn't mention you were doing an upgrade

It really doesn't matter technically b/c by default if you don't have MTU size it defaults to 1500, but for consistency, i would recommend removing it out of the RC file and then when you perform the upgrade you will have to do a takeover/giveback on each node and it will enter the running config.

Re: MTU config differ between filers

DHUCKSTEP — Tue, 20 May 2014 17:38:40 GMT

Thank you for the information.