Hello every body. Well, my question is very simple . I Have a HVM working fine ( I hope so ... ) on a CentOS 5.1 , xen 3.1. I created config file by hand .. I''m not using virtmanager from CentOS .. I '' m using LVM dev w/o file system formated. My HDA is configured like this: disk = [ ''phy:/dev/vms_1/win01,hda,w'' ] My question , what is the diference if I configure like this ... disk = [ ''phy:/dev/vms_1/win01,ioemu:hda,w'' ] What "ioemu" means ? Thanks Edison _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Friday 04 January 2008 10:39:45 pm virtual@ntsnet.com.br wrote:> My HDA is configured like this: > > disk = [ ''phy:/dev/vms_1/win01,hda,w'' ] > > My question , what is the diference if I configure like this ... > > disk = [ ''phy:/dev/vms_1/win01,ioemu:hda,w'' ] > > What "ioemu" means ?It''s simply a rudimentary attempt at ParaVirtual (PV) disk drivers on an HVM domain. Try it both ways, and ''cp'' a *new* file to or from your dom0 and HVM domain, and time the difference. (I say new file, so you don''tmeasure the effects of caching.) _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> > My HDA is configured like this: > > > > disk = [ ''phy:/dev/vms_1/win01,hda,w'' ] > > > > My question , what is the diference if I configure like this ... > > > > disk = [ ''phy:/dev/vms_1/win01,ioemu:hda,w'' ] > > > > What "ioemu" means ? > > It''s simply a rudimentary attempt at ParaVirtual (PV) disk drivers on an > HVM domain. Try it both ways, and ''cp'' a *new* file to or from your dom0 > and HVM domain, and time the difference. (I say new file, so you > don''tmeasure the effects of caching.)I don''t think the "ioemu" argument actually does anything for block devices anymore. As Jim suggested, it used to be used to specify whether a block device is an emulated (ioemu) or a paravirt disk. Nowadays, I think HVM supports both paravirt and emulated modes for each disk so the switch isn''t used. PV drivers need to be enabled explicitly in the HVM guest, so you won''t be able to measure a performance difference in IO unless you first install and configure these drivers. Cheers, Mark -- Dave: Just a question. What use is a unicyle with no seat? And no pedals! Mark: To answer a question with a question: What use is a skateboard? Dave: Skateboards have wheels. Mark: My wheel has a wheel! _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
>> > My HDA is configured like this:>> >>> > disk = [ ''phy:/dev/vms_1/win01,hda,w'' ]>> >>> > My question , what is the diference if I configure like this ...>> >>> > disk = [ ''phy:/dev/vms_1/win01,ioemu:hda,w'' ]>> >>> > What "ioemu" means ?>>>> It''s simply a rudimentary attempt at ParaVirtual (PV) disk drivers onan>> HVM domain. Try it both ways, and ''cp'' a *new* file to or from yourdom0>> and HVM domain, and time the difference. (I say new file, so you>> don''tmeasure the effects of caching.)>> I don''t think the "ioemu" argument actually does anything forblock devices> anymore. As Jim suggested, it used to be used to specify whether a block> device is an emulated (ioemu) or a paravirt disk. Nowadays, I think HVM> supports both paravirt and emulated modes for each disk so the switch isn''t> used.So ... it has no diference, right ? this is my question, I tested , and it worked on both way. For me ..make a copy from dom0 to domU has no sense, it use network. It is not a copy from a partition to another, because I''m using NTFS on a LVM virtual partition. Frorm my windows on DomU, I don''t have acess to Dom0 (centOS) file system and vice-versa ..>> PV drivers need to be enabled explicitly in the HVM guest, so you won''t be> able to measure a performance difference in IO unless you first install and> configure these drivers.>> Cheers,> Mark>> --> Dave: Just a question. What use is a unicyle with no seat? And no pedals!> Mark: To answer a question with a question: What use is a skateboard?> Dave: Skateboards have wheels.> Mark: My wheel has a wheel!>_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> So ... it has no diference, right ? this is my question, I tested , > and it workedIt shouldn''t make a difference to block devices. For net devices it still has some kind of effect, but for block it''s completely ignored.> on both way. For me ..make a copy from dom0 to domU has no sense, > it use > > network. It is not a copy from a partition to another, because I''m using > NTFS > > on a LVM virtual partition. Frorm my windows on DomU, I > don''t have acess > > to Dom0 (centOS) file system and vice-versa ..Well, I guess Jim meant to say that you should copy data from the VBD into the domU''s memory? Something like dd if=big_file of=/dev/null would achieve this, as a basic IO benchmark. But in any case... In an HVM domain you''ll always be using the emulated devices, unless you install PV drivers. In a PV domain you''re always using the PV drivers anyhow. The ioemu switch does not seem to have an effect for block devices anymore. Cheers, mark> > PV drivers need to be enabled explicitly in the HVM guest, so you won''t > > be > > > > > > able to measure a performance difference in IO unless you first install > > and > > > > > > configure these drivers. > > > > > > > > Cheers, > > > > Mark > > > > > > > > -- > > > > Dave: Just a question. What use is a unicyle with no seat? And no pedals! > > > > > > Mark: To answer a question with a question: What use is a skateboard? > > > > Dave: Skateboards have wheels. > > > > Mark: My wheel has a wheel! > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users-- Dave: Just a question. What use is a unicyle with no seat? And no pedals! Mark: To answer a question with a question: What use is a skateboard? Dave: Skateboards have wheels. Mark: My wheel has a wheel! _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Mon, Jan 07, 2008 at 01:31:53AM +0000, Mark Williamson wrote:
| But in any case... In an HVM domain you''ll always be using the
emulated
| devices, unless you install PV drivers. In a PV domain you''re always
using
| the PV drivers anyhow. The ioemu switch does not seem to have an effect for
| block devices anymore.
Hello ,
To have better performance on a HVM domain , i must install PV drivers .
Where i can find it ?
My dom0 is centos 5.1 , but my guest os can be centos 4 / debian etch,sarge .
--
____________________________________________________________
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| mailto:erwan@mas.nom.fr |_/
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On Mon, Jan 07, 2008 at 09:54:40AM +0100, Erwan MAS wrote:> On Mon, Jan 07, 2008 at 01:31:53AM +0000, Mark Williamson wrote: > | But in any case... In an HVM domain you''ll always be using the emulated > | devices, unless you install PV drivers. In a PV domain you''re always using > | the PV drivers anyhow. The ioemu switch does not seem to have an effect for > | block devices anymore. > > Hello , > > To have better performance on a HVM domain , i must install PV drivers . > > Where i can find it ? > > My dom0 is centos 5.1 , but my guest os can be centos 4 / debian etch,sarge . >I''m not sure if there are any easy-to-use rpm/deb packages available.. Linux Xen HVM PV drivers are included in the Xen source/mercurial tree. -- Pasi _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Mon, Jan 07, 2008 at 12:27:56PM +0200, Pasi Kärkkäinen wrote:
| On Mon, Jan 07, 2008 at 09:54:40AM +0100, Erwan MAS wrote:
| > On Mon, Jan 07, 2008 at 01:31:53AM +0000, Mark Williamson wrote:
| > | But in any case... In an HVM domain you''ll always be using
the emulated
| > | devices, unless you install PV drivers. In a PV domain you''re
always using
| > | the PV drivers anyhow. The ioemu switch does not seem to have an
effect for
| > | block devices anymore.
| >
| > To have better performance on a HVM domain , i must install PV drivers .
| > Where i can find it ?
| > My dom0 is centos 5.1 , but my guest os can be centos 4 / debian
etch,sarge .
|
| I''m not sure if there are any easy-to-use rpm/deb packages
available..
| Linux Xen HVM PV drivers are included in the Xen source/mercurial tree.
|
| -- Pasi
Which version of the source , i must take to compile ?
- The source used for building my hypervisor .
or
- The last version of xen 3.1 on the website .
( http://bits.xensource.com/oss-xen/release/3.1.0/src.tgz/xen-3.1.0-src.tgz from
http://www.xen.org/download/dl_31tarballs.html )
--
____________________________________________________________
/ Erwan MAS /\
| mailto:erwan@mas.nom.fr |_/
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> On Mon, Jan 07, 2008 at 01:31:53AM +0000, Mark Williamson wrote: > | But in any case... In an HVM domain you''ll always be using the emulated > | devices, unless you install PV drivers. In a PV domain you''re always > | using the PV drivers anyhow. The ioemu switch does not seem to have an > | effect for block devices anymore. > > Hello , > > To have better performance on a HVM domain , i must install PV drivers . > > Where i can find it ? > > My dom0 is centos 5.1 , but my guest os can be centos 4 / debian etch,sargeThey''re in the unmodified_drivers directory in the Xen source tree. To build these, you also need a copy of the XenLinux repository (although the build process might download that automatically for you). You then need to compile them for your kernel. Once you''ve done that I think you''d need to explicitly configure your system to actually use them so that it''ll access the disks using the PV drivers and not just let the driver of the emulated hardware grab those devices. Cheers, Mark -- Dave: Just a question. What use is a unicyle with no seat? And no pedals! Mark: To answer a question with a question: What use is a skateboard? Dave: Skateboards have wheels. Mark: My wheel has a wheel! _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users