After the swap off/on linux uses that swap area again. I believe what Ro b said/meant is that it doesn't reuse indiviual pages that it otherwise could/should.
The swap off/on makes it look brand new by wiping out all prior knowledge . Brian Nielsen On Mon, 3 Dec 2007 13:05:57 -0500, Romanowski, John (OFT) <[EMAIL PROTECTED]> wrote: >Rob said earlier that after linux starts using a lower priority swap >area it doesn't "migrate back from swap2 to swap1 when stuff is freed >later." > >So do you find after swapoff/on a high priority VDISK that linux starts >using it? or does it ignore it and keep filling the dasd swap? > > >-------------------------------------------------------- >This e-mail, including any attachments, may be confidential, privileged or otherwise legally protected. It is intended only for the addressee. If you received this e-mail in error or from someone who was not authorized to send it to you, do not disseminate, copy or otherwise use this e-mail or its attachments. Please notify the sender immediately by reply e-mail and delete the e-mail from your system. > > >-----Original Message----- > >From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On >Behalf Of Brian Nielsen >Sent: Monday, December 03, 2007 12:53 PM >To: [email protected] >Subject: Re: Is 275GB of VDISK stupid? > >On Mon, 3 Dec 2007 08:43:45 -0500, Romanowski, John (OFT) ><[EMAIL PROTECTED]> wrote: > >>Now that the swap topic's open again: >> >>What is the basis for advising z/VM VDISK users to have a hierarchy of >>multiple linux swap areas of increasing sizes? Are there feature(s) >of >>the swapping algorithm that make that hierarchy principle optimal? > >The configuration we use includes swap space on real DASD at a lower >priority than the VDISK swap areas. Over time Linux will swap more to >the >real DASD than the VDISKs. At this point doing a swap off and then on >of >a VDISK swap area frees up the fast VDISK. Having various VDISK sizes >allows the flexibility of migrating smaller amounts of swap data during >busy periods and larger amounts during slow periods. > >Brian Nielsen
