Re: [Xen-devel] Re: [Xen-users] Max. PV and HVM Guests

["Mr. Teo En Ming (Zhang Enming)" <space.time.universe@xxxxxxxxx>]

Hi All,

I have discovered that setting dom0_mem also solves another problem I am facing.

Previously I have complained that, after starting a HVM guest, in any pv-ops dom0 kernels 2.6.31.X, dom0 will be very slow, sluggish, and unresponsive, such that it is nearly impossible to start another HVM virtual machine.

Now, after setting dom0_mem, I booted up into pvops dom0 kernel 2.6.31.5, I started all 5 Rocks HPC cluster compute nodes at one go. And guess what? Dom0 is not even sluggish! I could still do desktop screen video capturing!

Voila! Setting dom0_mem is really killing two birds with one stone. It raises the number of VMs that I can start and also resolves the sluggishness in dom0 (pvops kernels 2.6.31.X affected; 2.6.30-rc3 is NOT affected) after starting a virtual machine.

Setting dom0_mem really does wonders.

Thank you Pasi!

-- 
Mr. Teo En Ming (Zhang Enming) Dip(Mechatronics) BEng(Hons)(Mechanical Engineering)
Alma Maters:
(1) Singapore Polytechnic
(2) National University of Singapore
My Primary Blog: http://teo-en-ming-aka-zhang-enming.blogspot.com
My Secondary Blog: http://enmingteo.wordpress.com
My Youtube videos: http://www.youtube.com/user/enmingteo
Email: space.time.universe@xxxxxxxxx
Mobile Phone (Starhub Prepaid): +65-8369-2618
Street: Bedok Reservoir Road
Country: Singapore

On Mon, Nov 9, 2009 at 9:10 PM, Mr. Teo En Ming (Zhang Enming) <space.time.universe@xxxxxxxxx> wrote:

Great! After setting dom0_mem=1024M, I can start all 5 nodes of my Rocks HPC cluster without crashing dom0 as compared to the previous limit of 3 nodes when I did not set dom0_mem.

Thank you Pasi! Another resource problem solved.

Here's my latest grub.conf:

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/mapper/vg_fedora11_host-lv_root
#          initrd /initrd-version.img
#boot=/dev/sda
default=4
timeout=100
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Fedora (2.6.31.5-xen-enming.teo)
    root (hd0,0)
#    kernel /vmlinuz-2.6.31.5-xen-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0
#    initrd /initrd-2.6.31.5-xen-enming.teo.img
    kernel /xen.gz dom0_mem=1024M iommu=1
    module /vmlinuz-2.6.31.5-xen-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0 nomodeset
    module /initrd-2.6.31.5-xen-enming.teo.img
title Fedora (2.6.31.4-xen-enming.teo)
    root (hd0,0)
#    kernel /vmlinuz-2.6.31.4-xen-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0
#    initrd /initrd-2.6.31.4-xen-enming.teo.img
    kernel /xen.gz dom0_mem=1024M iommu=1
    module /vmlinuz-2.6.31.4-xen-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0 nomodeset
    module /initrd-2.6.31.4-xen-enming.teo.img
title Fedora (2.6.31.1-xen-enming.teo)
    root (hd0,0)
#    kernel /vmlinuz-2.6.31.1-xen-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0
#    initrd /initrd-2.6.31.1-xen-enming.teo.img
    kernel /xen.gz dom0_mem=1024M iommu=1
    module /vmlinuz-2.6.31.1-xen-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0 nomodeset
    module /initrd-2.6.31.1-xen-enming.teo.img
title Fedora (2.6.31-enming.teo)
    root (hd0,0)
    kernel /vmlinuz-2.6.31-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0
    initrd /initrd-2.6.31-enming.teo.img
title Fedora (2.6.30.5-enming.teo)
    root (hd0,0)
    kernel /vmlinuz-2.6.30.5-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0
    initrd /initrd-2.6.30.5-enming.teo.img
title Fedora (2.6.18.8-enming.teo)
    root (hd0,0)
#    kernel /vmlinuz-2.6.18.8-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0
#    initrd /initrd-2.6.18.8-enming.teo.img
    kernel /xen.gz dom0_mem=1024M iommu=1
    module /vmlinuz-2.6.18.8-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root 
    module /initrd-2.6.18.8-enming.teo.img
title Fedora (2.6.31-rc6-enming.teo) with Serial Console
        root (hd0,0)
#       kernel /vmlinuz-2.6.31-rc6-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0
#       initrd /initrd-2.6.31-rc6-enming.teo.img
        kernel /xen.gz dom0_mem=1024M iommu=1 iommu_inclusive_mapping=1 com1=115200,8n1 console=com1
#       module /vmlinuz-2.6.31-rc6-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root selinux=0 xencons=ttyS0 console=ttyS0,115200
    module /vmlinuz-2.6.31-rc6-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root selinux=0 console=hvc0 earlyprintk=xen
        module /initrd-2.6.31-rc6-enming.teo.img
title Fedora (2.6.30-rc3-enming.teo-tip) with Serial Console
        root (hd0,0)
#       kernel /vmlinuz-2.6.30-rc3-enming.teo-tip ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0
#       initrd /initrd-2.6.30-rc3-enming.teo-tip.img
        kernel /xen.gz dom0_mem=1024M iommu=1 iommu_inclusive_mapping=1 com1=115200,8n1 console=com1
#       module /vmlinuz-2.6.30-rc3-enming.teo-tip ro root=/dev/mapper/vg_fedora11_host-lv_root selinux=0 xencons=ttyS0 console=ttyS0,115200
    module /vmlinuz-2.6.30-rc3-enming.teo-tip ro root=/dev/mapper/vg_fedora11_host-lv_root selinux=0 console=hvc0 earlyprintk=xen
        module /initrd-2.6.30-rc3-enming.teo-tip.img

title Fedora (2.6.31-rc6-enming.teo)
    root (hd0,0)
#    kernel /vmlinuz-2.6.31-rc6-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0
#    initrd /initrd-2.6.31-rc6-enming.teo.img
    kernel /xen.gz dom0_mem=1024M iommu=1
    module /vmlinuz-2.6.31-rc6-enming.teo ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0 nomodeset
    module /initrd-2.6.31-rc6-enming.teo.img
title Fedora (2.6.30-rc3-enming.teo-tip)
    root (hd0,0)
#    kernel /vmlinuz-2.6.30-rc3-enming.teo-tip ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0
#    initrd /initrd-2.6.30-rc3-enming.teo-tip.img
    kernel /xen.gz dom0_mem=1024M iommu=1
    module /vmlinuz-2.6.30-rc3-enming.teo-tip ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0 nomodeset
    module /initrd-2.6.30-rc3-enming.teo-tip.img
title Fedora (2.6.29.4-167.fc11.x86_64)
    root (hd0,0)
    kernel /vmlinuz-2.6.29.4-167.fc11.x86_64 ro root=/dev/mapper/vg_fedora11_host-lv_root rhgb quiet selinux=0
    initrd /initrd-2.6.29.4-167.fc11.x86_64.img

--
Mr. Teo En Ming (Zhang Enming) Dip(Mechatronics) BEng(Hons)(Mechanical Engineering)
Alma Maters:
(1) Singapore Polytechnic
(2) National University of Singapore
My Primary Blog: http://teo-en-ming-aka-zhang-enming.blogspot.com
My Secondary Blog: http://enmingteo.wordpress.com
My Youtube videos: http://www.youtube.com/user/enmingteo
Email: space.time.universe@xxxxxxxxx
Mobile Phone (Starhub Prepaid): +65-8369-2618
Street: Bedok Reservoir Road
Country: Singapore

On Mon, Nov 9, 2009 at 8:18 PM, Pasi Kärkkäinen <pasik@xxxxxx> wrote:

On Mon, Nov 09, 2009 at 08:14:27PM +0800, Mr. Teo En Ming (Zhang Enming) wrote:
>    What is a good value for dom0_mem if I want to start X server and run
>    GNOME? Will 512 MB be too little?
>

Go for 1024 MB then..

-- Pasi

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