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D Sims

2007-Mar-03 13:20 UTC

[Xen-users] Slow Disk access on SLES 10 install

I have been struggling with a problem for a couple of days and I hope someone
has some ideas.

I am using SLES 10 as a base for my Dom0 and I am trying to build a
paravirtualized guest domain.  

I have tried lots of combinations of things but the disk during the install
is increcdibly slow.  I am fairly certain that this is
something I have set wrong, as I see the same results on two very different
hardware platforms.  It takes about 2 hours for the first CD install; and
that time is the same if I use the cd drive as a source of my install or if
I use an NFS based source.


Below is my domain config file  --- I have tried lots of combinations of
things but still the same result.


--------------------------------------------------------------------------------------------------------------------------
disk = [ ''file:/var/lib/xen/images/basesles10/hda,hda,w'' ]
memory = 348
vcpus = 1
builder = ''linux''
kernel = ''/tmp/YaST2-04473-dmQhaD/vmlinuz-2.6.16.21-0.8-xen''
ramdisk = ''/tmp/YaST2-04473-dmQhaD/inst-initrd''
name = ''basesles10''
ip = ''192.168.1.253''
netmask = ''255.255.255.0''
gateway = ''192.168.1.1''
interface = ''eth0''
vif = [ ''mac=00:16:3e:d1:dc:36,bridge=xenbr0'',
''mac=00:16:3e:e2:e6:a0,bridge=xenbr1'' ]
localtime = 0
on_poweroff = ''destroy''
on_reboot = ''destroy''
on_crash = ''destroy''

import os, re
arch = os.uname()[4]
if re.search(''64'', arch):
    arch_libdir = ''lib64''
else:
    arch_libdir = ''lib''

device_model = ''/usr/'' + arch_libdir +
''/xen/bin/qemu-dm''


#----------------------------------------------------------------------------
# enable SDL library for graphics, default = 0
sdl=0

#----------------------------------------------------------------------------
# enable VNC library for graphics, default = 1
vnc=1

#----------------------------------------------------------------------------
# enable spawning vncviewer(only valid when vnc=1), default = 1
vncviewer=1

#----------------------------------------------------------------------------
# no graphics, use serial port
#nographic=0

#----------------------------------------------------------------------------
# enable stdvga, default = 0 (use cirrus logic device model)
stdvga=0

#-----------------------------------------------------------------------------
#   serial port re-direct to pty deivce, /dev/pts/n
#   then xm console or minicom can connect
serial=''pty''

#----------------------------------------------------------------------------
# enable ne2000, default = 0(use pcnet)
ne2000=0


#-----------------------------------------------------------------------------
#   enable audio support
#audio=1


#-----------------------------------------------------------------------------
#    set the real time clock to local time [default=0 i.e. set to utc]
#localtime=1


#-----------------------------------------------------------------------------
#    start in full screen
#full-screen=1

extra = ''install=nfs://192.168.1.9//opt/software/SLES10/disk1
TERM=xterm
textmode=0 vnc=1 hostip=192.168.1.253 netmask=255.255.255.0 ide=nodma
gateway=192.168.1.1 netdevice=eth0''

------------------------------------------------------------------------------------------------------------------

The ide=nodma is a farily recent addtion;  it did not seem at have any
effect on things.

Oddly, I did not see this when I used full virtualization.  That
installation was very normal.  

I am positive that I need to set something slightly different - I just do
not know what it it.

Thanks for any suggestions.
-- 
View this message in context:
http://www.nabble.com/Slow-Disk-access-on-SLES-10-install-tf3338478.html#a9284951
Sent from the Xen - User mailing list archive at Nabble.com.


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Matthias Lüneberg

2007-Mar-03 18:20 UTC

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Re: [Xen-users] Slow Disk access on SLES 10 install

Hi,

it seems to me that you use a file for the disk,
>disk = [ ''file:/var/lib/xen/images/basesles10/hda,hda,w'' ]
if you use a fresh SLES10 installation, you should read SLES10 Release
Notes:
http://www.novell.com/linux/releasenotes/i386/SUSE-SLES/10/RELEASE-NOTES.en.html
Theres a paragraph called: "Sync Mode for Loopback Storage" which
could
help.

Hope this helps!

Regards,
Matthias


Am Samstag, den 03.03.2007, 05:20 -0800 schrieb D Sims:> I have been struggling with a problem for a couple of days and I hope
someone
> has some ideas.
> 
> I am using SLES 10 as a base for my Dom0 and I am trying to build a
> paravirtualized guest domain.  
> 
> I have tried lots of combinations of things but the disk during the install
> is increcdibly slow.  I am fairly certain that this is
> something I have set wrong, as I see the same results on two very different
> hardware platforms.  It takes about 2 hours for the first CD install; and
> that time is the same if I use the cd drive as a source of my install or if
> I use an NFS based source.
> 
> 
> Below is my domain config file  --- I have tried lots of combinations of
> things but still the same result.
> 
> 
>
--------------------------------------------------------------------------------------------------------------------------
> disk = [ ''file:/var/lib/xen/images/basesles10/hda,hda,w''
]
> memory = 348
> vcpus = 1
> builder = ''linux''
> kernel =
''/tmp/YaST2-04473-dmQhaD/vmlinuz-2.6.16.21-0.8-xen''
> ramdisk = ''/tmp/YaST2-04473-dmQhaD/inst-initrd''
> name = ''basesles10''
> ip = ''192.168.1.253''
> netmask = ''255.255.255.0''
> gateway = ''192.168.1.1''
> interface = ''eth0''
> vif = [ ''mac=00:16:3e:d1:dc:36,bridge=xenbr0'',
> ''mac=00:16:3e:e2:e6:a0,bridge=xenbr1'' ]
> localtime = 0
> on_poweroff = ''destroy''
> on_reboot = ''destroy''
> on_crash = ''destroy''
> 
> import os, re
> arch = os.uname()[4]
> if re.search(''64'', arch):
>     arch_libdir = ''lib64''
> else:
>     arch_libdir = ''lib''
> 
> device_model = ''/usr/'' + arch_libdir +
''/xen/bin/qemu-dm''
> 
> 
>
#----------------------------------------------------------------------------
> # enable SDL library for graphics, default = 0
> sdl=0
> 
>
#----------------------------------------------------------------------------
> # enable VNC library for graphics, default = 1
> vnc=1
> 
>
#----------------------------------------------------------------------------
> # enable spawning vncviewer(only valid when vnc=1), default = 1
> vncviewer=1
> 
>
#----------------------------------------------------------------------------
> # no graphics, use serial port
> #nographic=0
> 
>
#----------------------------------------------------------------------------
> # enable stdvga, default = 0 (use cirrus logic device model)
> stdvga=0
> 
>
#-----------------------------------------------------------------------------
> #   serial port re-direct to pty deivce, /dev/pts/n
> #   then xm console or minicom can connect
> serial=''pty''
> 
>
#----------------------------------------------------------------------------
> # enable ne2000, default = 0(use pcnet)
> ne2000=0
> 
> 
>
#-----------------------------------------------------------------------------
> #   enable audio support
> #audio=1
> 
> 
>
#-----------------------------------------------------------------------------
> #    set the real time clock to local time [default=0 i.e. set to utc]
> #localtime=1
> 
> 
>
#-----------------------------------------------------------------------------
> #    start in full screen
> #full-screen=1
> 
> extra = ''install=nfs://192.168.1.9//opt/software/SLES10/disk1
TERM=xterm
> textmode=0 vnc=1 hostip=192.168.1.253 netmask=255.255.255.0 ide=nodma
> gateway=192.168.1.1 netdevice=eth0''
> 
>
------------------------------------------------------------------------------------------------------------------
> 
> The ide=nodma is a farily recent addtion;  it did not seem at have any
> effect on things.
> 
> Oddly, I did not see this when I used full virtualization.  That
> installation was very normal.  
> 
> I am positive that I need to set something slightly different - I just do
> not know what it it.
> 
> Thanks for any suggestions.

_______________________________________________
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Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

D Sims

2007-Mar-05 01:57 UTC

head link

Re: [Xen-users] Slow Disk access on SLES 10 install

Matthias:

You were 100% correct.  That was the piece of information that I did not
know that I needed.  As soon as I changed the setting in the
/etc/xen/scripts/block  script from

do_or_die losetup -y "$loopdev" "$file"

do_or_die losetup  "$loopdev" "$file"

this made all the difference in the world.  

However, this does beg another question. What is the best practice for
setting up a virtual disk for a guest domain?

Is it better to live with the possibility of data corruption on a host crash
and have normal disk access, or turn the flag on and be protected against
corruption, but suffer terrible performance.  Or is there a better way? 
Possibly to assign the guest domains their own disk partition that they can
write to as they please?  I have not tried this yet (I will tomorrow), but
that sounds like a better bet.  Or is there another way?

Thanks a ton for your help.

Dwain Sims





Hi,

it seems to me that you use a file for the disk,
>disk = [ ''file:/var/lib/xen/images/basesles10/hda,hda,w'' ]
if you use a fresh SLES10 installation, you should read SLES10 Release
Notes:
http://www.novell.com/linux/releasenotes/i386/SUSE-SLES/10/RELEASE-NOTES.en.html
Theres a paragraph called: "Sync Mode for Loopback Storage" which
could
help.

Hope this helps!

Regards,
Matthias


Am Samstag, den 03.03.2007, 05:20 -0800 schrieb D Sims:> I have been struggling with a problem for a couple of days and I hope
> someone
> has some ideas.
> 
> I am using SLES 10 as a base for my Dom0 and I am trying to build a
> paravirtualized guest domain.  
> 
> I have tried lots of combinations of things but the disk during the
> install
> is increcdibly slow.  I am fairly certain that this is
> something I have set wrong, as I see the same results on two very
> different
> hardware platforms.  It takes about 2 hours for the first CD install; and
> that time is the same if I use the cd drive as a source of my install or
> if
> I use an NFS based source.
> 
-- 
View this message in context:
http://www.nabble.com/Slow-Disk-access-on-SLES-10-install-tf3338478.html#a9303459
Sent from the Xen - User mailing list archive at Nabble.com.


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Ulrich Windl

2007-Mar-05 07:25 UTC

head link

Re: [Xen-users] Slow Disk access on SLES 10 install

On 3 Mar 2007 at 5:20, D Sims wrote:
> 
> I have been struggling with a problem for a couple of days and I hope
someone
> has some ideas.
> 
> I am using SLES 10 as a base for my Dom0 and I am trying to build a
> paravirtualized guest domain.  
> 
> I have tried lots of combinations of things but the disk during the install
> is increcdibly slow.  I am fairly certain that this is
> something I have set wrong, as I see the same results on two very different
> hardware platforms.  It takes about 2 hours for the first CD install; and
> that time is the same if I use the cd drive as a source of my install or if
> I use an NFS based source.
Pardon, but SLES10 is on DVD AFAIK.

Ulrich


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Per Andreas Buer

2007-Mar-05 17:41 UTC

head link

Re: [Xen-users] Slow Disk access on SLES 10 install

D Sims wrote:> Is it better to live with the possibility of data corruption on a host
crash
> and have normal disk access, or turn the flag on and be protected against
> corruption, but suffer terrible performance.  Or is there a better way? 
> Possibly to assign the guest domains their own disk partition that they can
> write to as they please?  I have not tried this yet (I will tomorrow), but
> that sounds like a better bet.  Or is there another way?
>   
lvm gives you normal performace - and as a bonus - snapshots. I can''t 
say whether this is integrated with YaST in any way.


Per.

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Daniel P. Berrange

2007-Mar-05 17:50 UTC

head link

Re: [Xen-users] Slow Disk access on SLES 10 install

On Sun, Mar 04, 2007 at 05:57:30PM -0800, D Sims wrote:> 
> Matthias:
> 
> You were 100% correct.  That was the piece of information that I did not
> know that I needed.  As soon as I changed the setting in the
> /etc/xen/scripts/block  script from
> 
> do_or_die losetup -y "$loopdev" "$file"
> 
> do_or_die losetup  "$loopdev" "$file"
> 
> this made all the difference in the world.  
> 
> However, this does beg another question. What is the best practice for
> setting up a virtual disk for a guest domain?
> 
> Is it better to live with the possibility of data corruption on a host
crash
> and have normal disk access, or turn the flag on and be protected against
> corruption, but suffer terrible performance.  Or is there a better way? 
Don''t use ''file:''  at all - loopback devices are just
not a viable storage
backend due to the horrific performance vs data integrity tradeoff you have
to make. A physical disk device is the best option, but failing that use 
blktap for file based disks. eg use the tap:aio:/var/lib/xen/images/foo.img
URL scheme for the disk.  NB, if you want good performance with file based
images, regardless of whether using blktap or loopback one should pre-allocate
the entire disk image. Grow-on-demand images are always going to be slow
because every time the host has to grow the image, it hits the journal on
the host filesystem.

Dan.
-- 
|=- Red Hat, Engineering, Emerging Technologies, Boston.  +1 978 392 2496 -=|
|=-           Perl modules: http://search.cpan.org/~danberr/              -=|
|=-               Projects: http://freshmeat.net/~danielpb/               -=|
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Xen users - Mar 2007 - Slow Disk access on SLES 10 install

[Xen-users] Slow Disk access on SLES 10 install

Re: [Xen-users] Slow Disk access on SLES 10 install

Re: [Xen-users] Slow Disk access on SLES 10 install

Re: [Xen-users] Slow Disk access on SLES 10 install

Re: [Xen-users] Slow Disk access on SLES 10 install

Re: [Xen-users] Slow Disk access on SLES 10 install