Where to set TCP data block size in Cloverleaf?

[Neal Brooks]

I have a vendor that acknowledges an issue where they take what they get across the socket per each send()/receive() and assume they have a message rather than gathering a message within an MLP envelope.  

For temporary fix until they resolve, they have asked for us to bump up the block buffer size transmitted each socket send() to 10kb.

I could not find anything on this attribute within this forum, nor do I see anything in the cis client that allows for this to be set.  

Can this be set within Cloverleaf?

(Cloverleaf 5.7.3 on Red Hat Enterprise)

Neal Brooks

Lead Integration Specialist

Memorial Health System of East Texas

Lufkin, Texas

nbrooks@memorialhealth.org

903.258.0587

Topic

[Robert Kersemakers]

Hi Neal,

No, I don’t think this can be set in Cloverleaf. It should be set in the OS. RHEL in your case.

I’m not a RHEL admin, so only very limited knowledge. Did a quick search and there seem to be various settings for this. You need a RHEL expert for this.

Zuyderland Medisch Centrum; Heerlen/Sittard; The Netherlands

[Russ Ross]

An OS configuration setting was my first thought, too.

If that is the case, keep in mind an OS configuration change for the TCP block size will likely effect all Cloverleaf interfaces and not just the one of interest.

Also, ask your system admin if that type of OS configuration change requires a server reboot to take effect.

Russ Ross
RussRoss318@gmail.com

[David Barr]

This sounds like some terrible socket programming on the part of your vendor. I hope they can fix this soon.

If you really want to try to change the size of the packets, you have to do it at a level that affects your entire system, and it’s not guaranteed to work because there could be other devices on your network that split the packets into smaller sizes. I’d do this on a test Cloverleaf system before attempting to change your production server.

I think the way you would do this would be to add MTU=10000 to /etc/sysconfig/network-scripts/ifcfg-eth0 and then either ifdown/ifup the interface (from a console because your terminal connection will probably drop) or reboot the server.

[Russ Ross]

Now that MTU has been mentioned this rings some bells for me.

Increasing the MTU size will most likely be a problem for other things.

Most remedies that invlove MTU settings from my past experience typically require the setting be lowered and not increased.

Russ Ross
RussRoss318@gmail.com

[Author]

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