Re: [ceph-users] Doesn't Support Qcow2 Disk images

[Wido den Hollander]

On 12-03-15 13:00, Lindsay Mathieson wrote:
> On Thu, 12 Mar 2015 12:49:51 PM Vieresjoki, Juha wrote:
>> But there's really no point, block storage is the only viable option for
>> virtual machines performance-wise. With images you're dealing with multiple
>> filesystem layers on top of the actual block devices, plus Ceph as block
>> storage supports pretty much everything that qcow2 as a format does.
> 
> 
> Not much difference that I've noticed on the small system I run, in fact 
> cepfs 
> seems to do some caching which speeds up things considerably in benchmarks. 
> Not a huge difference in actual app performance that I've noticed.
> 
> Delete/Restore of snapshots is a lot quicker with qcow2 and for somereasons 
> saving memory state is orders of magnitude quicker with qcow2.

Don't, simply don't run your VMs with QCOW2 over CephFS. You bring in so
much more complexity by adding a Posix Filesystem and the Ceph MDS.

Although CephFS might look faster due to the kernel caching, it's not safer!

Use RBD with Qemu, it keeps it all in userspace, a lot better then going
through all the kernelspace things.

Wido

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Re: [ceph-users] Doesn't Support Qcow2 Disk images

[Lindsay Mathieson]

On Thu, 12 Mar 2015 12:49:51 PM Vieresjoki, Juha wrote:
> But there's really no point, block storage is the only viable option for
> virtual machines performance-wise. With images you're dealing with multiple
> filesystem layers on top of the actual block devices, plus Ceph as block
> storage supports pretty much everything that qcow2 as a format does.


Not much difference that I've noticed on the small system I run, in fact cepfs 
seems to do some caching which speeds up things considerably in benchmarks. 
Not a huge difference in actual app performance that I've noticed.

Delete/Restore of snapshots is a lot quicker with qcow2 and for somereasons 
saving memory state is orders of magnitude quicker with qcow2.
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Re: [ceph-users] Doesn't Support Qcow2 Disk images

[Thomas Foster]

http://docs.openstack.org/image-guide/content/ch_converting.html
On Mar 12, 2015 6:50 AM, "Vieresjoki, Juha"  wrote:

> But there's really no point, block storage is the only viable option for
> virtual machines performance-wise. With images you're dealing with multiple
> filesystem layers on top of the actual block devices, plus Ceph as block
> storage supports pretty much everything that qcow2 as a format does.
>
> On 12 March 2015 at 12:18, Lindsay Mathieson 
> wrote:
>
>> On Thu, 12 Mar 2015 09:27:43 AM Andrija Panic wrote:
>> > ceph is RAW format - should be all fine...so VM will be using that RAW
>> > format
>>
>>
>> If you use cephfs you can use qcow2.
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>>
>
>
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Re: [ceph-users] Doesn't Support Qcow2 Disk images

[Vieresjoki, Juha]

But there's really no point, block storage is the only viable option for
virtual machines performance-wise. With images you're dealing with multiple
filesystem layers on top of the actual block devices, plus Ceph as block
storage supports pretty much everything that qcow2 as a format does.

On 12 March 2015 at 12:18, Lindsay Mathieson 
wrote:

> On Thu, 12 Mar 2015 09:27:43 AM Andrija Panic wrote:
> > ceph is RAW format - should be all fine...so VM will be using that RAW
> > format
>
>
> If you use cephfs you can use qcow2.
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Re: [ceph-users] Doesn't Support Qcow2 Disk images

[Lindsay Mathieson]

On Thu, 12 Mar 2015 09:27:43 AM Andrija Panic wrote:
> ceph is RAW format - should be all fine...so VM will be using that RAW
> format


If you use cephfs you can use qcow2.
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Re: [ceph-users] Doesn't Support Qcow2 Disk images

[Andrija Panic]

ceph is RAW format - should be all fine...so VM will be using that RAW
format

On 12 March 2015 at 09:03, Azad Aliyar  wrote:

> Community please explain the 2nd warning on this page:
>
> http://ceph.com/docs/master/rbd/rbd-openstack/
>
> "Important Ceph doesn’t support QCOW2 for hosting a virtual machine disk.
> Thus if you want to boot virtual machines in Ceph (ephemeral backend or
> boot from volume), the Glance image format must be RAW."
>
>
> --
>Warm Regards,  Azad Aliyar
>  Linux Server Engineer
>  *Email* :  azad.ali...@sparksupport.com   *|*   *Skype* :   spark.azad
>  
> 
> 
> 3rd Floor, Leela Infopark, Phase
> -2,Kakanad, Kochi-30, Kerala, India  *Phone*:+91 484 6561696 , 
> *Mobile*:91-8129270421.
>   *Confidentiality Notice:* Information in this e-mail is proprietary to
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-- 

Andrija Panić
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[ceph-users] Doesn't Support Qcow2 Disk images

[Azad Aliyar]

Community please explain the 2nd warning on this page:

http://ceph.com/docs/master/rbd/rbd-openstack/

"Important Ceph doesn’t support QCOW2 for hosting a virtual machine disk.
Thus if you want to boot virtual machines in Ceph (ephemeral backend or
boot from volume), the Glance image format must be RAW."


-- 
   Warm Regards,  Azad Aliyar
 Linux Server Engineer
 *Email* :  azad.ali...@sparksupport.com   *|*   *Skype* :   spark.azad
 

  
3rd Floor, Leela Infopark, Phase -2,Kakanad, Kochi-30, Kerala, India
*Phone*:+91 484 6561696 , *Mobile*:91-8129270421.   *Confidentiality
Notice:* Information in this e-mail is proprietary to SparkSupport. and is
intended for use only by the addressed, and may contain information that is
privileged, confidential or exempt from disclosure. If you are not the
intended recipient, you are notified that any use of this information in
any manner is strictly prohibited. Please delete this mail & notify us
immediately at i...@sparksupport.com
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