Thanks but I may not have made the goal clear, or I miss understand the instructions. The app is stuffing certain data into swap. The use case does not see enough of a performance increase to warrant the non technical result of high swap usage. Adding swap, moving swap etc does not resolve the issue. I need to flush swap without shutting down the process consuming 42 of the 48Gb of ram on the box. Once flushed I can set swapiness to something low. On 11/4/10, Lisa Kachold wrote: > On Thu, Nov 4, 2010 at 5:58 PM, Bryan O'Neal < > Bryan.ONeal@theonealandassociates.com> wrote: > >> Setting swapiness is how I can deal with a recurrence but it will not >> flush current swap. And I can not shut down any process to perform >> swap off. :( >> >> On 11/4/10, Eric Shubert wrote: >> > On 11/04/2010 03:26 PM, Bryan O'Neal wrote: >> >> Please no debates on why I need to clear swap... >> >> >> >> If I have a box with 20% free ram and 5% free swap but no paging >> >> activity - how do I force linux to release the allocated swap? I have >> >> ~ 2x as much allocated swap as free memory so simply turning swap off >> >> seems like a bad idea. >> >> >> >> Thanks >> >> >> > >> > To minimize swap use, put >> > vm.swappiness = 0 >> > in /etc/sysctl.conf file. You can also change it on the fly in the >> > /proc/sys/vm/swappiness. >> > See http://unixfoo.blogspot.com/2007/11/linux-performance-tuning.html >> > >> > AFA purging the swap file is concerned, I only know to stop and start it >> > again: >> > # swapoff -a && swapon -a >> > You might not run into trouble doing this, as there's probably a good >> > deal of (filesystem) cached ram being used that the kernel will give up >> > if it's needed for running processes. Do the math though to be sure you >> > won't run out. Either that or stop some less important processes while >> > you do it. >> > >> > -- >> > -Eric 'shubes' >> > >> >> > I would leave the current swap, in case you start thrashing, however, you > requested we not debate, here's the howto: > > Type following command to create 512MB swap file (1024 * 512MB = 524288 > block size): > > # dd if=/dev/zero of=/swapfile1 bs=1024 count=524288 > > c) Set up a Linux swap area: > # mkswap /swapfile1 > > d) Activate /swapfile1 swap space immediately: > # swapon /swapfile1 > > e) To activate /swapfile1 after Linux system reboot, add entry to /etc/fstab > file. Open this file using text editor such as vi: > # vi /etc/fstab > > Append following line: > /swapfile1 swap swap defaults 0 0 > And comment out the old swapfile. You can swapoff the old file also, but I > would, in a production machine test the full swap utilization after changes > through a reboot. > > -- > Skype: 6022393392 > ATT: 5037544452 > GV: 6236883392 > http://www.it-clowns.com > Politicians should read science fiction, not westerns and detective stories. > -Arthur C. Clark I am free because I know that I alone am morally > responsible for everything I do. -Heinlein > -- Sent from my mobile device --------------------------------------------------- PLUG-discuss mailing list - PLUG-discuss@lists.plug.phoenix.az.us To subscribe, unsubscribe, or to change your mail settings: http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-discuss