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Old 09-11-2011, 09:52 PM
"Thomas Dukes"
 
Default Vitualization and Partitioning

Hello,

OK, getting ready to order a new machine and had some questions about 6.0.
It will have a single 500GB HD.

When I do the install, do I or should I setup a separate partition for guest
OS's? From the redhat docs, it looks like the guest OS's reside at
/var/lib/libvirt/images/. I may combine my windoze XP on the CentOS machine
so would I need to create a partition and format that at installation? If I
decide to wait and go with Windoze 7 can I still create the partition later?

I would like a partition scheme that allows for easier upgrades or installs
without losing data.

Thanks, I'm more confused now that when I started reading about this stuf..

Eddie

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Old 09-12-2011, 03:10 AM
Emmanuel Noobadmin
 
Default Vitualization and Partitioning

Hi,

> When I do the install, do I or should I setup a separate partition for guest
That would be better from a performance point of view

> OS's? From the redhat docs, it looks like the guest OS's reside at
> /var/lib/libvirt/images/.
This should be using files as disk files, which I did and found it to
be a problem when there is heavy I/O.

>I may combine my windoze XP on the CentOS machine
> so would I need to create a partition and format that at installation? If I
> decide to wait and go with Windoze 7 can I still create the partition later?
>
> I would like a partition scheme that allows for easier upgrades or installs
> without losing data.

Try using LVM then, it allows you to create and resize logical
partitions, including expanding with additional hard disks in the
future without having to reconfigure your VM guest (except the usual
file system expansion steps)

> Thanks, I'm more confused now that when I started reading about this stuf..

That's my experience too, the more we read, the more
alternatives/options there are, the more confusing it gets!
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Old 09-12-2011, 04:35 AM
ken
 
Default Vitualization and Partitioning

On 09/11/2011 11:10 PM Emmanuel Noobadmin wrote:
> Hi,
>
>> When I do the install, do I or should I setup a separate partition for guest
> That would be better from a performance point of view
>
>> OS's? From the redhat docs, it looks like the guest OS's reside at
>> /var/lib/libvirt/images/.
> This should be using files as disk files, which I did and found it to
> be a problem when there is heavy I/O.

I like LVM (for the reasons you cite). Would you (anyone?) say it's
best to have one LV per guest or one LV for all guests?


tnx.

> ....

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Old 09-12-2011, 11:52 PM
"Thomas Dukes"
 
Default Vitualization and Partitioning

> -----Original Message-----
> From: centos-bounces@centos.org
> [mailto:centos-bounces@centos.org] On Behalf Of ken
> Sent: Monday, September 12, 2011 12:36 AM
> To: CentOS mailing list
> Subject: Re: [CentOS] Vitualization and Partitioning
>
> On 09/11/2011 11:10 PM Emmanuel Noobadmin wrote:
> > Hi,
> >
> >> When I do the install, do I or should I setup a separate partition
> >> for guest
> > That would be better from a performance point of view
> >
> >> OS's? From the redhat docs, it looks like the guest OS's reside at
> >> /var/lib/libvirt/images/.
> > This should be using files as disk files, which I did and
> found it to
> > be a problem when there is heavy I/O.
>
> I like LVM (for the reasons you cite). Would you (anyone?)
> say it's best to have one LV per guest or one LV for all guests?
>
>
> tnx.

I'm new to this but I would think you would want a separate LV for each
guest. Seems I read somewhere, that you need one core per guest as well.
That's why I'm opting for the Xeon processor rather than the iCore(x). Four
cores v. two. More options.

Can't believe this thread hasn't stirred more response. Maybe we all are in
the learning phase.

Eddie

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Old 09-13-2011, 05:01 AM
Trey Dockendorf
 
Default Vitualization and Partitioning

On Mon, Sep 12, 2011 at 6:52 PM, Thomas Dukes <tdukes@sc.rr.com> wrote:





> -----Original Message-----

> From: centos-bounces@centos.org

> [mailto:centos-bounces@centos.org] On Behalf Of ken

> Sent: Monday, September 12, 2011 12:36 AM

> To: CentOS mailing list

> Subject: Re: [CentOS] Vitualization and Partitioning

>

> On 09/11/2011 11:10 PM Emmanuel Noobadmin wrote:

> > Hi,

> >

> >> When I do the install, do I or should I setup a separate partition

> >> for guest

> > That would be better from a performance point of view

> >

> >> OS's? From the redhat docs, it looks like the guest OS's reside at

> >> /var/lib/libvirt/images/.

> > This should be using files as disk files, which I did and

> found it to

> > be a problem when there is heavy I/O.

>

> I like LVM (for the reasons you cite). *Would you (anyone?)

> say it's best to have one LV per guest or one LV for all guests?

>

>

> tnx.



I'm new to this but I would think you would want a separate LV for each

guest. Seems I read somewhere, that you need one core per guest as well.

That's why I'm opting for the Xeon processor rather than the iCore(x). Four

cores v. two. More options.



Can't believe this thread hasn't stirred more response. Maybe we all are in

the learning phase.



Eddie



_______________________________________________

CentOS mailing list

CentOS@centos.org

http://lists.centos.org/mailman/listinfo/centos


An LV per guest isn't necessary, but has its benefits. *What I did on one of my server was a use two drives in RAID 1 for the system and then a RAID 6 array for the VM storage. *I've opted to use QCow2 images for the virtual disks, so they all go on a LV I created "/vmstore" where all virtual disks go. *I always try to keep the system paritions (/ and /boot)*separate*from the data (with virtual server, I use /vmstore , or /var/lib/libvirt/images) at least logically, if not physically. *My biggest consideration between LVM and image files for the VM disks was snapshot capabilities. *While LVM can do snapshots using lvm's native tools, it still requires extra steps to get the VM's memory (if still running). *That considered I saw no benefit in my case to use LVM when some other tools could combine the ability to do both qcow2 and memory snapshotting at once. *Plus in my environment it is easier to work with a single virtual disk file than deal with LVMs.
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Old 09-13-2011, 08:30 AM
Rudi Ahlers
 
Default Vitualization and Partitioning

On Tue, Sep 13, 2011 at 1:52 AM, Thomas Dukes <tdukes@sc.rr.com> wrote:
>
>
>> -----Original Message-----
>> From: centos-bounces@centos.org
>> [mailto:centos-bounces@centos.org] On Behalf Of ken
>> Sent: Monday, September 12, 2011 12:36 AM
>> To: CentOS mailing list
>> Subject: Re: [CentOS] Vitualization and Partitioning
>>
>> On 09/11/2011 11:10 PM Emmanuel Noobadmin wrote:
>> > Hi,
>> >
>> >> When I do the install, do I or should I setup a separate partition
>> >> for guest
>> > That would be better from a performance point of view
>> >
>> >> OS's? From the redhat docs, it looks like the guest OS's reside at
>> >> /var/lib/libvirt/images/.
>> > This should be using files as disk files, which I did and
>> found it to
>> > be a problem when there is heavy I/O.
>>
>> I like LVM (for the reasons you cite). *Would you (anyone?)
>> say it's best to have one LV per guest or one LV for all guests?
>>
>>
>> tnx.
>
> I'm new to this but I would think you would want a separate LV for each
> guest. Seems I read somewhere, that you need one core per guest as well.
> That's why I'm opting for the Xeon processor rather than the iCore(x). Four
> cores v. two. More options.
>
> Can't believe this thread hasn't stirred more response. Maybe we all are in
> the learning phase.
>
> Eddie
>
> _______________________________________________

We use LVM on all our virtual hosting servers since it's much easier to manage.


You basically setup a PV volume spanning the whole drive(s), and then
a 10GB (or larger if you need to) LVM volume for /root, 10GB for /var,
2GB for /tmp & 5GB for /home.


Then for any VM's just add LVM volumes as needed, for example:

/dev/Volume001/vm1_root - 10GB
/dev/Volume001/vm1_swap - 1GB


Another tip: Don't use the default LVM volume naming scheme, but
instead name the LVM volumes according to your server name, i.e.
server01 & server02. This way if server01's HDD crashes and you need
to mount it on server002 for recovery purposes, you won't have
conflicting LVM volumes


--
Kind Regards
Rudi Ahlers
SoftDux

Website: http://www.SoftDux.com
Technical Blog: http://Blog.SoftDux.com
Office: 087 805 9573
Cell: 082 554 7532
_______________________________________________
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Old 09-13-2011, 10:38 AM
Indunil Jayasooriya
 
Default Vitualization and Partitioning

On Tue, Sep 13, 2011 at 2:00 PM, Rudi Ahlers <Rudi@softdux.com> wrote:
> On Tue, Sep 13, 2011 at 1:52 AM, Thomas Dukes <tdukes@sc.rr.com> wrote:
>>
>>
>>> -----Original Message-----
>>> From: centos-bounces@centos.org
>>> [mailto:centos-bounces@centos.org] On Behalf Of ken
>>> Sent: Monday, September 12, 2011 12:36 AM
>>> To: CentOS mailing list
>>> Subject: Re: [CentOS] Vitualization and Partitioning
>>>
>>> On 09/11/2011 11:10 PM Emmanuel Noobadmin wrote:
>>> > Hi,
>>> >
>>> >> When I do the install, do I or should I setup a separate partition
>>> >> for guest
>>> > That would be better from a performance point of view
>>> >
>>> >> OS's? From the redhat docs, it looks like the guest OS's reside at
>>> >> /var/lib/libvirt/images/.
>>> > This should be using files as disk files, which I did and
>>> found it to
>>> > be a problem when there is heavy I/O.
>>>
>>> I like LVM (for the reasons you cite). *Would you (anyone?)
>>> say it's best to have one LV per guest or one LV for all guests?
>>>
>>>
>>> tnx.
>>
>> I'm new to this but I would think you would want a separate LV for each
>> guest. Seems I read somewhere, that you need one core per guest as well.
>> That's why I'm opting for the Xeon processor rather than the iCore(x). Four
>> cores v. two. More options.
>>
>> Can't believe this thread hasn't stirred more response. Maybe we all are in
>> the learning phase.
>>
>> Eddie
>>
>> _______________________________________________
>
> We use LVM on all our virtual hosting servers since it's much easier to manage.
>
>
> You basically setup a PV volume spanning the whole drive(s), and then
> a 10GB (or larger if you need to) LVM volume for /root, 10GB for /var,
> 2GB for /tmp & 5GB for /home.
>
>
> Then for any VM's just add LVM volumes as needed, for example:
>
> /dev/Volume001/vm1_root *- 10GB
> /dev/Volume001/vm1_swap - 1GB
>
>
> Another tip: Don't use the default LVM volume naming scheme, but
> instead name the LVM volumes according to your server name, i.e.
> server01 & server02. This way if server01's HDD crashes and you need
> to mount it on server002 for recovery purposes, you won't have
> conflicting LVM volumes
>
>

Hi, Interesting subject. Let me participate too. Suppose we are going
to install 3 VMs, I think it is proper to create separate LVMs like
this

/dev/vg_server1/lv.server1

and mount it as

/var/lib/libvirt/images/server1



/dev/vg_server2/lv.server2

and mount it as

/var/lib/libvirt/images/server2



/dev/vg_server3/lv.server3

and mount it as

/var/lib/libvirt/images/server3



If I mount in that way, Is it possible to take live snapshot backup
while these 2 servers are running?


Hope to hear from you..






> --
> Kind Regards
> Rudi Ahlers
> SoftDux
>
> Website: http://www.SoftDux.com
> Technical Blog: http://Blog.SoftDux.com
> Office: 087 805 9573
> Cell: 082 554 7532
> _______________________________________________
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
>



--
Thank you
Indunil Jayasooriya
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Old 09-13-2011, 11:59 AM
Dennis Jacobfeuerborn
 
Default Vitualization and Partitioning

On 09/13/2011 12:38 PM, Indunil Jayasooriya wrote:
> On Tue, Sep 13, 2011 at 2:00 PM, Rudi Ahlers<Rudi@softdux.com> wrote:
>> On Tue, Sep 13, 2011 at 1:52 AM, Thomas Dukes<tdukes@sc.rr.com> wrote:
>>>
>>>
>>>> -----Original Message-----
>>>> From: centos-bounces@centos.org
>>>> [mailto:centos-bounces@centos.org] On Behalf Of ken
>>>> Sent: Monday, September 12, 2011 12:36 AM
>>>> To: CentOS mailing list
>>>> Subject: Re: [CentOS] Vitualization and Partitioning
>>>>
>>>> On 09/11/2011 11:10 PM Emmanuel Noobadmin wrote:
>>>>> Hi,
>>>>>
>>>>>> When I do the install, do I or should I setup a separate partition
>>>>>> for guest
>>>>> That would be better from a performance point of view
>>>>>
>>>>>> OS's? From the redhat docs, it looks like the guest OS's reside at
>>>>>> /var/lib/libvirt/images/.
>>>>> This should be using files as disk files, which I did and
>>>> found it to
>>>>> be a problem when there is heavy I/O.
>>>>
>>>> I like LVM (for the reasons you cite). Would you (anyone?)
>>>> say it's best to have one LV per guest or one LV for all guests?
>>>>
>>>>
>>>> tnx.
>>>
>>> I'm new to this but I would think you would want a separate LV for each
>>> guest. Seems I read somewhere, that you need one core per guest as well.
>>> That's why I'm opting for the Xeon processor rather than the iCore(x). Four
>>> cores v. two. More options.
>>>
>>> Can't believe this thread hasn't stirred more response. Maybe we all are in
>>> the learning phase.
>>>
>>> Eddie
>>>
>>> _______________________________________________
>>
>> We use LVM on all our virtual hosting servers since it's much easier to manage.
>>
>>
>> You basically setup a PV volume spanning the whole drive(s), and then
>> a 10GB (or larger if you need to) LVM volume for /root, 10GB for /var,
>> 2GB for /tmp& 5GB for /home.
>>
>>
>> Then for any VM's just add LVM volumes as needed, for example:
>>
>> /dev/Volume001/vm1_root - 10GB
>> /dev/Volume001/vm1_swap - 1GB
>>
>>
>> Another tip: Don't use the default LVM volume naming scheme, but
>> instead name the LVM volumes according to your server name, i.e.
>> server01& server02. This way if server01's HDD crashes and you need
>> to mount it on server002 for recovery purposes, you won't have
>> conflicting LVM volumes
>>
>>
>
> Hi, Interesting subject. Let me participate too. Suppose we are going
> to install 3 VMs, I think it is proper to create separate LVMs like
> this
>
> /dev/vg_server1/lv.server1
>
> and mount it as
>
> /var/lib/libvirt/images/server1
>
>
>
> /dev/vg_server2/lv.server2
>
> and mount it as
>
> /var/lib/libvirt/images/server2
>
>
>
> /dev/vg_server3/lv.server3
>
> and mount it as
>
> /var/lib/libvirt/images/server3

Don't use separate volume groups. Also don't mount the logical volumes but
instead use them directly as block devices. That should give you better
performance as the i/o path is then VM->block device instead of
VM->filesystem->block device.

> If I mount in that way, Is it possible to take live snapshot backup
> while these 2 servers are running?

Remember that you need to allocate enough space for the snapshot volume to
contain all the blocks that change on the VM while the backup is running
i.e. if your backup is running for an hour and during that hour your VM
receives 2G worth of writes/update then you need to have at least a size of
2G for your snapshot volume.
This also means that you have to reserve enough space in the volume group
to create a big enough snapshot volume.

Also keep in mind that the backup you will get will not be fully consistent
only crash consistent.

Regards,
Dennis
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Old 09-13-2011, 04:57 PM
Rajagopal Swaminathan
 
Default Vitualization and Partitioning

On Tue, Sep 13, 2011 at 10:31 AM, Trey Dockendorf <treydock@gmail.com> wrote:
>
> That considered I saw no benefit in my
> case to use LVM when some other tools could combine the ability to do both
> qcow2 and memory snapshotting at once.

Could you kindly share with us the tools you which could do both?

Another (may unrelated) question:

Has anybody installed or migrated a Netware 3.12 using KVM?

If so, can you please share the experiences? especially bits about
Netware partitioning and the NIC model that needs to be selected?

TIA

--
Regards,

Rajagopal
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Old 09-13-2011, 09:10 PM
Trey Dockendorf
 
Default Vitualization and Partitioning

On Tue, Sep 13, 2011 at 11:57 AM, Rajagopal Swaminathan <raju.rajsand@gmail.com> wrote:

On Tue, Sep 13, 2011 at 10:31 AM, Trey Dockendorf <treydock@gmail.com> wrote:

>

> That considered I saw no benefit in my

> case to use LVM when some other tools could combine the ability to do both

> qcow2 and memory snapshotting at once.



Could you kindly share with us the tools you which could do both?



Another (may unrelated) question:



Has anybody installed or migrated a Netware 3.12 using KVM?



If so, can you please share the experiences? especially bits about

Netware partitioning and the NIC model that needs to be selected?



TIA



--

Regards,



Rajagopal

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CentOS mailing list

CentOS@centos.org

http://lists.centos.org/mailman/listinfo/centos



I've only successfully tested using virt-manager to do snapshots. *There is a way using virsh, doing "snapshot-create domain", but I receive an error due to lack of that feature.

error: internal error unable to execute QEMU command 'savevm': The command savevm has not been found
Using the virsh "save" command works, but only does it without shutting down the VM if done through virt-manager. *Other tools that look promising for snapshots thus far are things like Convirt, OpenQRM, and Archipel, but I have yet to get them in production to test that out.

- Trey
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