Hi,
For Hipersockets and SAP/db2 connect transactional workloads the default
MTU of 8k is suggested. Keep in mind to change TCPRCVBUFRSIZE and
TCPSENDBFRSIZE in z/OS TCPIP settings as well as net.ipv4.tcp_wmem in
zLinux accordingly. For performance reasons, it is suggested to increase
qeth buffer count for the HiperSockets devices as well.
You can see some of this information in the recent redbook draft (p39 - 47):
http://www.redbooks.ibm.com/redpieces/abstracts/sg246847.html
Regards, Joerg
Joerg Maier
Developer
IBM System z
SAP AG
Raiffeisenring 45
68789 St. Leon-Rot Germany
T: 06227-7-44027
F: 06227-78-46257
mailto:joerg.ma...@sap.com
www.sap.com
Rich Smrcina wrote:
Plan to make the MTU size about the average size of the result set
that application
returns. That will probably be very difficult to determine, but
probably the easiest
way to find out will be to ask the developers how large the queries
typically are. Of
course there will be variations and it will be prudent to ask if
applications are
planned that will return larger result sets.
If they are larger than 64K, then your task is certain.
If they return a few small rows (it's more transactional) then a
smaller MTU may be best.
bruce.light...@its.ms.gov wrote:
We are just now setting up our first hipersocket connection(s) from z/VM
and linux to z/OS and will primarily use this first cut for DB2
connect to
talk to DB2 on z/OS. Does anyone have a guide for the MTU size? (
redbook,
whitepaper, etc )
Thanks,
Bruce Lightsey
Mississippi Dept. of Information Technology Services
301 N. Lamar St., Suite 508
Jackson, Ms 39201-1495
(601) 359-2644 voice (601) 359-1394 fax
www.its.ms.gov www.ms.gov
mailto:bruce.light...@its.ms.gov
--
Rich Smrcina
VM Assist, Inc.
Phone: 414-491-6001
Ans Service: 360-715-2467
http://www.linkedin.com/in/richsmrcina
Catch the WAVV! http://www.wavv.org
WAVV 2009 - Orlando, FL - May 15-19, 2009
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