[Users] New setup - deploy OpenVZ or wait for VZ7?

Konstantin Khorenko khorenko at virtuozzo.com
Mon Jun 6 08:13:13 PDT 2016


On 06/06/2016 02:23 PM, Volker Janzen wrote:
> Hi Sergey,
>
>> On 14:39 Sun 05 Jun , Volker Janzen wrote:
>>>>
>>>> Unfortunately no. We don't support upgrade from pre-release version to the final one.
>>>
>>> When I use a CentOS 7 as base system and install VZ7 afterward it's not possible to upgrade, too?
>>
>> There is only one supported configuration for new installations -
>> clean Virtuozzo 7 installation.
>
> okay I see. My setup will be unsupported if installed on plain CentOS 7 either way.
>
>>
>>>>> It also seems to lack some documentation for my use cases, but I need to start
>>>>> with VZ7 sooner or later.
>>>>
>>>> What usecases are you talking about?
>>>
>>> My current OpenVZ setup has LVM involved.
>>> I want to be able to use simfs based storage on an underlaying LVM volume.
>>
>> Why do you prefer simfs instead of ploop? Did you see comparison simfs vs ploop?
>> https://openvz.org/CT_storage_backends
>
> I think you asked me about this some time ago. The matrix states: Reliability
> Low: big amount of files produce ext4 corruption so often
>
> Why should I use something that tells me it's not reliable?

Even according to
https://github.com/pavel-odintsov/OpenVZ_ZFS/blob/master/openvz_storage_backends.md
(which seems to be used as a source of recent page update) this row is incorrect, this info has just been added by Narcis Garcia and is to be corrected.

i don't want to start a holly war here, i won't tell that ZFS is worse or whatever,
i just know that we really do power crash testing and know the results.
And i'm certain that our default suggested solution is good and stable.

Yes, there are drawbacks - the most important one now is usage overhead (sic!, not stability for a long time already), and we improve it.
And gained quite a good progress. Just did a ploop compaction of my personal work Container, created 03.07.2014 (lot of gits, makes, etc.):

# ploop-balloon discard /vz/private/105/root.hdd/DiskDescriptor.xml --defrag
...
# ploop-balloon discard /vz/private/105/root.hdd/DiskDescriptor.xml --stat
Balloon size:        0MB
Data size:       29189MB
Ploop size:     102400MB
Image size:      29057MB

Yes, i know it's still possible to create an image which will be compacted not that efficiently, but this becomes quite a rare case.
Do you have such an image? Send it to us.

Thank you.

P.S. in fact we don't need full image in most cases, only metadata is essential, so if you worry about data and confidentiality, no problem here:
# e2image -r /dev/ploopXXp1 - | bzip2 > image.e2i.bz2

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

> The /vz partition has also the big advantage of using LVM snapshots and it allows rsync of the container data to another host with less overhead.
>
> Also the need to compress the ploop files does not seem to be something I'm willing to do.
>
>
> Regards
>     Volker
>
>>
>>> And I want to be able to setup KVM based VMs that have a LVM based disk, too.
>>> In best case KVM VMs can be created from a template, as with the container VMs.
>>
>> Den, is it possible in Vz7?
>>
>>> Regards
>>>    Volker


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