HI Pasi,
thanks for your cooperation,this the XML configuration VM file
name = "vm2"
uuid = "70bf5c52-91ed-fbd5-4eb7-f6acc52c3168"
maxmem = 2277
memory = 1024
vcpus = 1
bootloader = "/usr/bin/pygrub"
kernel = "/var/lib/xen/boot_kernel.313tN4"
ramdisk = "/var/lib/xen/boot_ramdisk.vV9Kd9"
extra = "ro root=/dev/VolGroup00/LogVol00 rhgb quiet"
on_poweroff = "destroy"
on_reboot = "restart"
on_crash = "restart"
vfb = [ "type=vnc,vncunused=1,keymap=en-us" ]
disk = [ "tap:aio:/var/lib/xen/images/vm2.img,xvda,w" ]
vif = [
"mac=00:16:36:1e:3a:dc,bridge=virbr0,script=vif-bridge,vifname=vif2.0"
]
i am new user for xen so i think maybe you the backend in xen tap:aio ??
how can be sure the VM cache is empty with out restart VM??
--- On Sun, 7/24/11, Pasi Kärkkäinen
<pasik@iki.fi> wrote:
From: Pasi Kärkkäinen <pasik@iki.fi>
Subject: Re: [Xen-users] how can empty xen disk cache??
To: "Radhya sahal" <rad_cs_2006@yahoo.com>
Cc: "xen list" <xen-users@lists.xensource.com>
Date: Sunday, July 24, 2011, 3:21 AM
On Sat, Jul 23, 2011 at 06:46:58PM -0700, Radhya sahal
wrote:> thank''s Mark and Pasi,
> i use centos and xen ,either dom0 and vm run centos 5.5.
> in the vm i run java application which it reads e.g( text file ,table in
> database,....).
> in the first read get actual total run-time but if i try to read more
than
> one . the file be in cache and get a very very short time ..!!!
> although i try to empty
the vm cache and physical(dom0) cache!!!> echo 3 >/proc/sys/vm/drop_caches
> i want to read more than one to calculate the the right average run-time
for
> the vm resource allocation and compare this averages with other vm
resource
> allocations ???
>
I repeat the question: Which disk backend are you using in dom0 for the VM ?
-- Pasi
> --- On Sat, 7/23/11, Pasi Kärkkäinen <pasik@iki.fi> wrote:
>
> From: Pasi Kärkkäinen <pasik@iki.fi>
> Subject: Re: [Xen-users] how can empty xen disk cache??
> To: "Mark Pryor" <tlviewer@yahoo.com>
> Cc: "Radhya sahal" <rad_cs_2006@yahoo.com>,
> "xen-users@lists.xensource.com"
<xen-users@lists.xensource.com>
> Date: Saturday, July 23, 2011, 6:44 AM
>
> On Fri, Jul 22, 2011 at 07:11:57PM -0700, Mark Pryor wrote:
> >
>
--------------------------------------------------------------------------
> >
> > From: Radhya sahal <rad_cs_2006@yahoo.com>
> > To: xen-users@lists.xensource.com
> > Sent: Friday, July 22, 2011 5:36 PM
> > Subject: [Xen-users] how can empty xen disk cache??
> >
> > hi
> > I am new user for xen
> > i have VM and i run java application on it ..
> > i want to empty cache for vm
> > i do that with
> > echo 3 >/proc/sys/vm/drop_caches
>
> and the same command in physical machine> > but there is not any effect
> > i think the vm have own cache in xen
> > how can empty xen disk cache??
> > thanks
> >
> > check options in /etc/sysconfig/xendomains or (etc/default --
in
> debian)
> > and turn off save/restore.
> >
>
> I don''t think the question has nothing to do with
save/restore.
>
> Dom0 does not usually cache domU disk IO, unless you''re using
file:
> backend.
> Which disk backends are you using?
>
>
tap:aio and phy: backends bypass the dom0 page cache,> and thus those backends don''t have any caching in xen dom0.
>
> Xen hypervisor itself does not have cache of any kind.
>
> -- Pasi
_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users
