2009/5/8 Tomasz Westrych <[email protected]>: > How to clear memory cache in Sles 9 ? In SLES10 you can do "echo 3 > > /proc/sys/vm/drop_caches". > In SLES9 I, don't see drop_caches. > > We have z/VM 5.4 + SLES9 version 2.6.5-7.244-s390x.
Right. This is a more recent addition to Linux memory management, and it's not available in the older kernels. Be aware that it does not really help you in reducing your real memory requirements when running on z/VM. The reason is that z/VM is not aware that Linux has freed up those pages, and z/VM will still retain the data. In some cases, doing this will actually *increase* your real memory requirements. If you want to do such things, look at CMM-1 (which is in SLES9). It's really just a diagnostics tool, for example to make sure that your benchmark is no cheating with a lot of data already loaded in cache. It may also be helpful to understand the base requirements of an application. And for those of the other side listening in: there is a bug in one of the RHEL5 kernels that causes Linux in a loop when you use drop_caches in a very large server. Rob -- Rob van der Heij Velocity Software http://www.velocitysoftware.com/ ---------------------------------------------------------------------- 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
