>Hi
>
>I have one question about running linux on z/VM and z/VM memory
>management.
>
>My current environment (production)
>
>Total real memory = 12GB
>Total page volumes = +- 5GB
>Total memory allocation to linux servers (guests) = 7104MB (+- 7GB)
>Paging usage = 40 - 50% (2GB - 2.5GB)
>XSTORE = 2GB (just recently added after noticing paging did happen in
z/VM though we have enough real memory)
>
>Main storage used by z/VM is only 5GB (meaning at any one time, 2 GB or
more will be swapped off)
>
>Operating Systems:
>z/VM 4.4
>SLES 8.1 SP4 (31-bit)
>
>I observed that by default, memory mode for linux guest is V=V. Hence,
>z/VM takes control of memory management. Since I have enough real
>memory, why z/VM
>still does the paging? Any way to avoid paging on z/VM. I would prefer
>to let linux server to have real memory (V=R). Any comments on this? And
>how to set it in the user direct? Any fine-tuning can be done?
You observe the z/VM 2GB mitigation. An excellent source of information is
the z/VM performance website:
http://www.vm.ibm.com/perf/tips/2gstorag.html
>
>I also heard that V=R will not be supported in z/VM 5.1. Is it true?
Yes the V=R support is dropped in z/VM 5.1. More details are to be find
here:
http://www.vm.ibm.com/perf/tips/z890.html
>
>Thanks for your attention.
>
>Regards,
>Johnny Tan
Regards / Mit freundlichen Gruessen
Mario Held
Linux - architecture and performance
IBM Germany Lab, Schoenaicher Str. 220, 71032 Boeblingen
--
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
