MTU（ jumbo frame） settings?

[xyzeratul]

Hi I recently upgrade my main switch to a 4 port 2.5G + 2 port 10G SPF+ mode, I plan to install 10G nic on my unraid and desktop PC, and use 2.5G usb nic on my laptop.

 

because I was on 1G network before, I never touch the MTU, always leave it as 1500, but I hear 2.5G and 10G nic may need setup jumbo frame(MTU 9000）on them, and it's best for every client in the network has the same MTU.

 

Should I enable the jumbo frame on my PC, NAS and laptop in this case?

[itimpi]

Jumbo frames can cause more trouble than they are worth for only a small performance gain (if any).  I would leave them set to current value.   They are something that sounds much better in theory than has proved to actually be the case.

[MAM59]

Stay away from Jumbo Frames. They once were introduced to limit the amount of CPU time to calculate / check each frame when 1G LAN was introduced.

The idea was that with larger frames, the percentage of the needed header would decrease and less CPU would be hogged.

 

These were the days of "dumb" LAN cards.

Today even the cheapest Realtek one can do the calculations "onchip" and therefor allow "offloading" these things.

 

So, the "Time for Jumbo Frames" is gone for a decade or more already. Today they are just ghosts that need to be included for backwards compatibility reasons.

 

If you did not use them before, don't even think about using them now.

 

(Mesmerizing: "...shhhhh, forget you have ever heard about them.... shhhhhhh....") 😉

[xyzeratul]

11 hours ago, MAM59 said:

Stay away from Jumbo Frames. They once were introduced to limit the amount of CPU time to calculate / check each frame when 1G LAN was introduced.

The idea was that with larger frames, the percentage of the needed header would decrease and less CPU would be hogged.

 

These were the days of "dumb" LAN cards.

Today even the cheapest Realtek one can do the calculations "onchip" and therefor allow "offloading" these things.

 

So, the "Time for Jumbo Frames" is gone for a decade or more already. Today they are just ghosts that need to be included for backwards compatibility reasons.

 

If you did not use them before, don't even think about using them now.

 

(Mesmerizing: "...shhhhh, forget you have ever heard about them.... shhhhhhh....") 😉

OK got it, so no need to change MTU on 2.5G or 10G NIC.