RE: RAC interconnect packet size??

From: Bobak, Mark <>
Date: Tue, 21 Apr 2009 08:52:19 -0400
Message-ID: <>

Hi Joe,

You definitely *want* jumbo frames. Problem is ensuring that your hardware will support jumbo frames! This means all NICs that are dedicated to interconnect traffic as well as the switch (you have a physically dedicated switch for interconnect traffic, right?) must support jumbo frames.

We just enabled jumbo frames on our production RAC this past weekend. We were able to test in preprod first, and so far, we've had no issues with it.

As to whether or not it's doing any good, well, we were suffering from periodic "storms" of heavy interconnect activity, with lots of gc waits. We're playing wait and see now, but we're hoping that we no longer see that type of problem.


From: [] On Behalf Of Sent: Tuesday, April 21, 2009 8:14 AM
Subject: RAC interconnect packet size??

We tried to use 9000 MTU on the interconnect and were getting intermittent node evictions due to communication errors, for those of you running RAC, are you using jumbo frames on your network cards and switch(es)? We've had to back down to 1500 for reliability.

HP DL380-G5, 64G of ram, 3 nodes.

Just looking to see what everyone else is doing.

thanks., joe

Joe Testa, Oracle Certified Professional Senior Consultant
Data Engineering and Administration
Nationwide Investments

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Received on Tue Apr 21 2009 - 07:52:19 CDT

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