10:33 a.m.
I used kvm/virt-manager heavily in Fedora 11 (helped me a GREAT deal
in getting my RHCT).
Now, I'm trying to use it again in Fedora 13 to prepare for my RHCE,
but I'm finding it a LOT slower. I can't install with an ISO image on
my external driver (using ntfs-3g), it keeps failing with a
permissions error. However, if I copy my ISO over to my home folder,
and it picks it up. I also tried using the actual RHEL 5.5 and 5.4
CD's that I have to install from, but even though it's mounted and I
can view the contents in Nautilus, virt-manager says that /dev/sr0 has
no media present.
So I tried to store the (preallocated raw) VM image on my external
driver, but that fails too. So I have to have my VM virtio disk file
on the same hard drive that the ISO is on trying to do the install,
which takes nearly 20 hours installing RHEL 5.4.
I did manage to get 5.5 installed before on this (by leaving it
running overnight), but the performance was terrible.
Also, I thought Fedora 13 was supposed to automagically set up virtual
bridges for the VMs to use, but the only option I have is NAT, it says
that there are no bridges configured, even though I have a virbr0
interface when I run ifconfig.
Any help would be appreciated, as I have no desire to install VritualBox.
-Kenny
10:41 a.m.
On Thu, May 27, 2010 at 11:33:35AM -0400, Kenneth Armstrong wrote:
I used kvm/virt-manager heavily in Fedora 11 (helped me a GREAT deal
in getting my RHCT).
Now, I'm trying to use it again in Fedora 13 to prepare for my RHCE,
but I'm finding it a LOT slower.
The classic reason would be that you're not using KVM, but reverting
to software emulation (ie. pure qemu). Did you install the guest with
acceleration enabled? Is kvm-*.ko loaded? What are the permissions
on /dev/kvm? What's in the libvirt XML for the domain?
I can't install with an ISO image on
my external driver (using ntfs-3g), it keeps failing with a
permissions error.
Whether or not this is selinux, this sounds like you should file a BZ.
It clearly should be a supported configuration.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
New in Fedora 11: Fedora Windows cross-compiler. Compile Windows
programs, test, and build Windows installers. Over 70 libraries supprt'd
http://fedoraproject.org/wiki/MinGW http://www.annexia.org/fedora_mingw
12:29 p.m.
Thanks Rich,
I do have kvm_intel loaded, and I did verify that I'm using kvm as the
hypervisor and not qemu.
Something that occured to me is that I am using BTRFS with Fedora 13
instead of EXT4, which is what I was using under F11. I was under the
impression that BTRFS was actually a bit quicker than EXT4 though.
I do have SELinux enabled, but I'm not getting any AVC warnings.
On Thu, May 27, 2010 at 11:41 AM, Richard W.M. Jones <rjones(a)redhat.com> wrote:
On Thu, May 27, 2010 at 11:33:35AM -0400, Kenneth Armstrong wrote:
> I used kvm/virt-manager heavily in Fedora 11 (helped me a GREAT deal
> in getting my RHCT).
>
> Now, I'm trying to use it again in Fedora 13 to prepare for my RHCE,
> but I'm finding it a LOT slower.
The classic reason would be that you're not using KVM, but reverting
to software emulation (ie. pure qemu). Did you install the guest with
acceleration enabled? Is kvm-*.ko loaded? What are the permissions
on /dev/kvm? What's in the libvirt XML for the domain?
> I can't install with an ISO image on
> my external driver (using ntfs-3g), it keeps failing with a
> permissions error.
Whether or not this is selinux, this sounds like you should file a BZ.
It clearly should be a supported configuration.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
New in Fedora 11: Fedora Windows cross-compiler. Compile Windows
programs, test, and build Windows installers. Over 70 libraries supprt'd
http://fedoraproject.org/wiki/MinGW http://www.annexia.org/fedora_mingw
1:26 p.m.
Thanks Cole,
I filed this bug report:
https://bugzilla.redhat.com/show_bug.cgi?id=596902
On Thu, May 27, 2010 at 1:29 PM, Kenneth Armstrong <digimars(a)gmail.com> wrote:
Thanks Rich,
I do have kvm_intel loaded, and I did verify that I'm using kvm as the
hypervisor and not qemu.
Something that occured to me is that I am using BTRFS with Fedora 13
instead of EXT4, which is what I was using under F11. I was under the
impression that BTRFS was actually a bit quicker than EXT4 though.
I do have SELinux enabled, but I'm not getting any AVC warnings.
On Thu, May 27, 2010 at 11:41 AM, Richard W.M. Jones <rjones(a)redhat.com> wrote:
> On Thu, May 27, 2010 at 11:33:35AM -0400, Kenneth Armstrong wrote:
>> I used kvm/virt-manager heavily in Fedora 11 (helped me a GREAT deal
>> in getting my RHCT).
>>
>> Now, I'm trying to use it again in Fedora 13 to prepare for my RHCE,
>> but I'm finding it a LOT slower.
>
> The classic reason would be that you're not using KVM, but reverting
> to software emulation (ie. pure qemu). Did you install the guest with
> acceleration enabled? Is kvm-*.ko loaded? What are the permissions
> on /dev/kvm? What's in the libvirt XML for the domain?
>
>> I can't install with an ISO image on
>> my external driver (using ntfs-3g), it keeps failing with a
>> permissions error.
>
> Whether or not this is selinux, this sounds like you should file a BZ.
> It clearly should be a supported configuration.
>
> Rich.
>
> --
> Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
> New in Fedora 11: Fedora Windows cross-compiler. Compile Windows
> programs, test, and build Windows installers. Over 70 libraries supprt'd
> http://fedoraproject.org/wiki/MinGW http://www.annexia.org/fedora_mingw
>
1:57 p.m.
On Thu, May 27, 2010 at 01:29:25PM -0400, Kenneth Armstrong wrote:
Something that occured to me is that I am using BTRFS with Fedora 13
instead of EXT4, which is what I was using under F11. I was under the
impression that BTRFS was actually a bit quicker than EXT4 though.
I wonder how well btrfs deals with modifying files? In an classic
"wandering tree" implementation files are persistent, and modifying a
file would involve a copy. I don't know how far btrfs goes down that
route though.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-df lists disk usage of guests without needing to install any
software inside the virtual machine. Supports Linux and Windows.
http://et.redhat.com/~rjones/virt-df/
6:19 a.m.
On 05/27/2010 08:29 PM, Kenneth Armstrong wrote:
Something that occured to me is that I am using BTRFS with Fedora 13
instead of EXT4, which is what I was using under F11. I was under the
impression that BTRFS was actually a bit quicker than EXT4 though.
btrfs is slower than ext4, especially with cache=writethrough. Try
cache=writeback to recover some of the performance loss.
ext4 is slower as well due to defaulting to barrier=1. barrier=0 will
be faster at the cost of data integrity.
For best performance, use LVM and cache=off.
--
error compiling committee.c: too many arguments to function
7:24 a.m.
Thanks, I had actually reinstalled and used ext4 (I was already using
LVM) the other day, and my performance has improved tremendously. I
had no idea that btrfs was that slow. Thanks for the other tips
though.
-Kenny
On Sun, May 30, 2010 at 7:19 AM, Avi Kivity <avi(a)redhat.com> wrote:
On 05/27/2010 08:29 PM, Kenneth Armstrong wrote:
>
> Something that occured to me is that I am using BTRFS with Fedora 13
> instead of EXT4, which is what I was using under F11. I was under the
> impression that BTRFS was actually a bit quicker than EXT4 though.
>
>
btrfs is slower than ext4, especially with cache=writethrough. Try
cache=writeback to recover some of the performance loss.
ext4 is slower as well due to defaulting to barrier=1. barrier=0 will be
faster at the cost of data integrity.
For best performance, use LVM and cache=off.
--
error compiling committee.c: too many arguments to function
8:04 a.m.
On 05/30/2010 03:24 PM, Kenneth Armstrong wrote:
Thanks, I had actually reinstalled and used ext4 (I was already
using
LVM) the other day, and my performance has improved tremendously. I
had no idea that btrfs was that slow. Thanks for the other tips
though.
LVM without ext4 (each guest disk mapped directly to a logical volume)
will be faster still, though you will need to allocate all space ahead
of time.
--
error compiling committee.c: too many arguments to function
10:24 a.m.
Ok, so it would be even better to have a separate partition that is
just LVM with no filesystem, and just have raw disk images stored
there for the VM's then? That makes a lot of sense, I'll have to try
that out. Is that what RHEV is doing? Thanks again!
On Sun, May 30, 2010 at 9:04 AM, Avi Kivity <avi(a)redhat.com> wrote:
On 05/30/2010 03:24 PM, Kenneth Armstrong wrote:
>
> Thanks, I had actually reinstalled and used ext4 (I was already using
> LVM) the other day, and my performance has improved tremendously. I
> had no idea that btrfs was that slow. Thanks for the other tips
> though.
>
LVM without ext4 (each guest disk mapped directly to a logical volume) will
be faster still, though you will need to allocate all space ahead of time.
--
error compiling committee.c: too many arguments to function
5:27 a.m.
On Sun, May 30, 2010 at 11:24:05AM -0400, Kenneth Armstrong wrote:
Ok, so it would be even better to have a separate partition that is
just LVM with no filesystem, and just have raw disk images stored
there for the VM's then? That makes a lot of sense, I'll have to try
that out. Is that what RHEV is doing? Thanks again!
RHEV does something slightly different, but yes using LVM partitions
directly for guests is the way to go (at least, for performance, this
configuration is less flexible). To allocate a new guest, I do:
# lvcreate -n GuestName -L 8G vg_hostname
# virt-install -v -n GuestName --accelerate \
-r 1024 -f /dev/vg_hostname/GuestName \
--cdrom [path to CD or other install method]
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
libguestfs lets you edit virtual machines. Supports shell scripting,
bindings from many languages. http://et.redhat.com/~rjones/libguestfs/
See what it can do: http://et.redhat.com/~rjones/libguestfs/recipes.html
10:54 a.m.
On 05/27/2010 11:33 AM, Kenneth Armstrong wrote:
I used kvm/virt-manager heavily in Fedora 11 (helped me a GREAT deal
in getting my RHCT).
Now, I'm trying to use it again in Fedora 13 to prepare for my RHCE,
but I'm finding it a LOT slower. I can't install with an ISO image on
my external driver (using ntfs-3g), it keeps failing with a
permissions error. However, if I copy my ISO over to my home folder,
and it picks it up.
This has to do with libvirt now running VMs as the unprivileged 'qemu'
user. Probably a result of not being able to set an selinux label on the
media. You might be able to work around it by temporarily disabling
selinux with 'getenforce 0'
I also tried using the actual RHEL 5.5 and 5.4
CD's that I have to install from, but even though it's
mounted and I
can view the contents in Nautilus, virt-manager says that /dev/sr0 has
no media present.
I believe F13 doesn't do CDROM media polling by default anymore. On F12
at least this can be changed with:
hal-disable-polling --device /dev/sr0 --enable-polling
There is also a virt-manager fix upstream to allow using a CDROM device
even if no media was detected. Fix will be backported shortly:
https://bugzilla.redhat.com/show_bug.cgi?id=583616
So I tried to store the (preallocated raw) VM image on my external
driver, but that fails too. So I have to have my VM virtio disk file
on the same hard drive that the ISO is on trying to do the install,
which takes nearly 20 hours installing RHEL 5.4.
I did manage to get 5.5 installed before on this (by leaving it
running overnight), but the performance was terrible.
Like Rich said, maybe new VMs were accidentally using plain QEMU.
virt-manager in F13 does a poor job warning about this situation, but
rawhide is better, and the patches will be backported:
https://bugzilla.redhat.com/show_bug.cgi?id=582324
Also, I thought Fedora 13 was supposed to automagically set up
virtual
bridges for the VMs to use, but the only option I have is NAT, it says
that there are no bridges configured, even though I have a virbr0
interface when I run ifconfig.
virbr0 is the virtual bridge device created for NAT networking, it's not
a 'shared physical device' type bridge that gives your VMs a real IP
address. We don't create one of the latter out of the box.
- Cole
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10 comments
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participants (4)
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Kenneth Armstrong -
Richard W.M. Jones