On Wed, 29 Sep 2004 08:11:24 -0500, James Melin <[EMAIL PROTECTED]> wrote:
> So how do you set /proc/sys/vm/bdflush so that it remains from IPL to IPL? Easiest is probably through /etc/sysctl.conf and running sysctl as part of the boot process. Once you know what you need in there. The thing that bdflush deals with is when data is being written to disk. Linux delays writing to disk a little in case the data is going to change again real soon. The trigger for writing to disk is in time as well as percentage of memory. The longer you wait writing it out, the more I/O you avoid. It may very well be that extreme configurations don't go well with the defaults (e.g. let so much "dirty" pages build up that it takes ages to get that written out). This does not address the issue that Linux keeps data in memory just in case it is needed again. But I am not sure that needs to be addressed either. For discrete servers (and LPAR) that is probably a good thing if you don't need the memory for something else (for Linux on z/VM that is *not* a good thing because it affects the footprint). What we are seeing lately with some installations is that Linux appears so eager to keep data in memory (i.e. data backed by files on disk) that it starts to swap out processes. That does not seem to be the right way... -- Rob van der Heij rvdheij @ gmail.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
