HI everyone. This post has created some confusion within my VM group and I wanted to see if I understand XSTORE and MDC. Linux does not utilize XSTORE for MiniDisk Cache and you are better off using XSTORE for VM paging. Especially if you over commit VDISK swap space. We tend to overcommit swap just by the nature of how we clone. VM's default setting assumes MDC is meant to improve disk performance for VM guests. Is this pretty close or am I way off base? Al Schilla State of Minnesota
-----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] Behalf Of Rob van der Heij Sent: Wednesday, March 23, 2005 9:38 AM To: [email protected] Subject: Re: Expanded Storage On Wed, 23 Mar 2005 10:02:00 -0500, Levy, Alan <[EMAIL PROTECTED]> wrote: > XSTORE= 1024M online= 1024M > XSTORE= 1024M userid= SYSTEM usage= 99% retained= 0M pending= 0M > XSTORE MDC min=0M, max=1024M, usage=12% > XSTORE= 1024M userid= (none) max. attach= 1024M I would recommend to disable MDC in XSTORE, iirc with SET MDC XSTORE 0M 0M The rationale behind that is that you have XSTORE as a fast route for paging - especially to give CP room to arrange things under the 2G bar. You do not want your expanded storage as a disk cache (you rather had main memory if it were for that). I believe MDC in main memory *is* useful, but the defaults make it often too agressive (I like to set the ratio much lower than 1, but others prefer to set a max). This is different when main memory is less than 2G because that does not have the 2G issue and is very small to allow for some MDC benefits. 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 ---------------------------------------------------------------------- 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
