For what's it's worth, we aren't currently running SAP or Oracle but we do run several applications with tomcat. We were able to cut down the virtual storage required by the tomcat guests dramatically by using 4 VDISK's for swap. For example, one vendor stated they needed 1 GIG of memory. But we now run their product with 96Meg. The performance Redbook was a big help. Don't just look at overcommit'ing memory. Look at using VDISK's to cut back on real memory usage.
-----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] Behalf Of Lufthansa Systems Infratec ZLINUX SYSPROG Sent: Friday, October 15, 2004 2:12 AM To: [EMAIL PROTECTED] Subject: Overcommit memory Dear all, there is a lot to read about z/VM and Linux performance. Also about memory over commit. but I didn`t find "real life" performance data about zLinux & SAP or Oracle or Tomcat (nor other "standard" Application-Server) and how the perform while over commit memory. A special point of interest would be: - How many escon-channels do you use for swap under z/VM ? - How much (in percent) do you over commit memory for a Linux-guest ? - What`s about fibre-channel ? Is there a much better performance and is it possible to do much more memory over commit ? - If yes, how much more ? As I can say so far, 20% memory over commitment in general works. We us 4 escon-channels to the z/VM swap-devices. I would be happy, if someone can share some "real life" experience with us. Regards, Martin Lonkwitz Martin Lonkwitz Lufthansa Systems GmbH UNIX Systems Engineer FRA AR/ISS Systemplanung,-betrieb Am Weiher 24 und Entwicklung D-65451 Kelsterbach Telefon:(069) 696-72456 Externer Servicepartner der Firma networker, projektberatung GmbH Am Kaltenborn 1 61462 K�nigstein ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 This communication, including attachments, is for the exclusive use of addressee and may contain proprietary, confidential or privileged information. If you are not the intended recipient, any use, copying, disclosure, dissemination or distribution is strictly prohibited. If you are not the intended recipient, please notify the sender immediately by return email and delete this communication and destroy all copies. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
