On Fri, Sep 29, 2006 at 01:47:07PM -0400, Yu Safin wrote: > On 9/29/06, Adam Thornton <[EMAIL PROTECTED]> wrote: > >On Sep 29, 2006, at 7:09 AM, [EMAIL PROTECTED] wrote: > > > >> My past installations have used 4 same-sized v-disk areas with > >> ascending > >> priorities. I was under the impression that Linux references an entire > >> v-disk when it goes to swap, so smaller v-disks would be more > >> efficient. > >> But I'm not sure that's completely true. I want to simplify the fstab > >> configuration and reduce the potential memory footprint, so I'm > >> thinking > >> of 1 moderate size v-disk, backed by 1 larger lower-priority DASD. The > >> pair can be sized to whatever the applications require. > >> > >> Does anyone have a swap setup that optimizes performance and resource > >> usage, i.e., more small v-disks vs fewer big ones, inclusion of real > >> disk, etc.? > > > >Depending on how big the guest is, I usually cascade three swap > >VDISKS of increasing size and decreasing (meaning the pri= number > >gets bigger), and then if I need it, a big swap on real disk below that. > > > >You could eliminate two of these VDISKS if you wanted. > > > >Adam > > > >---------------------------------------------------------------------- > >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 > > > We had problems when we ran out of SWAP space and the system locked up. > At that time we had a v-disk of 512 MB only. We added two more SWAP > spaces with a lower priority of 2 GB each. The linux guest machine > has 4 GB of real memory defined. I have noticed that going over 512 > GB of SWAP on the v-disk is a very rare occurence. am I better off > with two additional SWAP spaces or should I break them up into smaller > ones? > To speed up the access to the swap space use multiple disks at the same priority. So to take the above example instead of using one 512 MB disk use four 128 MB disks with the same priority. To see how much I/O is done to the swap space run vmstat and look at the swap coloums.
Best regards/Mit freundlichen Grüßen Ihno Krumreich "Never trust a computer you can lift." -- Ihno Krumreich [EMAIL PROTECTED] SUSE LINUX Products GmbH Projectmanager S390 & zSeries Maxfeldstr. 5 +49-911-74053-439 D-90409 Nürnberg http://www.suse.de ---------------------------------------------------------------------- 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
