[Users] OpenVZ and ZFS excellent experience

Pavel Odintsov pavel.odintsov at gmail.com
Sun Jan 11 08:45:17 PST 2015


Hello, folks!

I read your message again and found suggestion about decreasing block
size of ploop. But unfortunately it's not possible with vzctl in any
ways. We can do it only with direct call of ploop.

Because I can't change block size or recreate VE with another block
size I tried to do some research about space lost with current block
size.

I wrote tool for checking amount of wasted space in ploop:
https://gist.github.com/pavel-odintsov/d5c37316e538908e0f01

Sorry, I'm not a good pythoner and any
feedback/hate/complains/optimizations about this code are welcome.

Everyone can check how many space it can save if reduce ploop block size.

Some data from me:

We count 5276434432 bytes
We count 1360051876 zero bytes
We count 3916382556 non zero bytes
We have 25.775965 % of space lost due to ploop fragmentation

We count 1105199104 bytes
We count 509808990 zero bytes
We count 595390114 non zero bytes
We have 46.128249 % of space lost due to ploop fragmentation

On Sat, Jan 10, 2015 at 5:50 PM, Pavel Odintsov
<pavel.odintsov at gmail.com> wrote:
> Hello!
>
> Thank you! I will contact with you out off list.
>
> On Sat, Jan 10, 2015 at 4:44 PM, Kirill Korotaev <dev at parallels.com> wrote:
>> Pavel,
>>
>> it’s impossible to analyze it just by `du` and `df` output, so please give me access if you want me to take a look into it.
>> (e.g. if I would create 10 million of 1KB files du would show me 10GB while ext4 (and most other file systems) would allocate 40GB in reality assuming 4KB block size)
>>
>> Thanks,
>> Kirill
>>
>>
>>> On 10 Jan 2015, at 00:54, Pavel Odintsov <pavel.odintsov at gmail.com> wrote:
>>>
>>> Thank you, Kirill! I am grateful for your answer!
>>>
>>> I reproduced this issue specially for you on one container with 2.4
>>> times (240% vs 20%) overuse.
>>>
>>> I do my tests with current vzctl and ploop 1.12.2 (with fixed
>>> http://bugzilla.openvz.org/show_bug.cgi?id=3156).
>>>
>>> Please check this gist:
>>> https://gist.github.com/pavel-odintsov/b2162c0f7588bb8e5c15
>>>
>>> I can't describe this behavior without complying on ext4 data.... But
>>> I I will be very happy if you fix it :)
>>>
>>> On Sat, Jan 10, 2015 at 12:29 AM, Kirill Korotaev <dev at parallels.com> wrote:
>>>>
>>>>> On 09 Jan 2015, at 21:39, Pavel Odintsov <pavel.odintsov at gmail.com> wrote:
>>>>>
>>>>> Hello, everybody!
>>>>>
>>>>> Do somebody have any news about ZFS and OpenVZ experience?
>>>>>
>>>>> Why not?
>>>>>
>>>>> Did you checked my comparison table for simfs vs ploop vs ZFS volumes?
>>>>> You should do it ASAP:
>>>>> https://github.com/pavel-odintsov/OpenVZ_ZFS/blob/master/openvz_storage_backends.md
>>>>>
>>>>> Still not interesting?
>>>>>
>>>>> For example if you have 5Tb disk array (used up to 90%) and using
>>>>> ploop now you lose about 800GB of disk space!
>>>>
>>>> Well, AFAIR we simply have a threshold that ploop is not compacted until it’s size is 20% bigger then it should be…
>>>> Also you can try smaller ploop block size. Anyway, my point is that it has nothing to do with ext4 metadata as stated in your table.
>>>>
>>>>
>>>>> This data is from real HWN with few hundreds of containers.
>>>>>
>>>>> I have excellent experience and very good news about ZFS! ZFS on Linux
>>>>> team will add very important feature, linux quota inside container
>>>>> (more details here https://github.com/zfsonlinux/zfs/pull/2577
>>>>>
>>>>> But still no news about ZFS from OpenVZ team (and even from Virtuozza
>>>>> Core) and we can work separately :)
>>>>>
>>>>> Fortunately, we do not need any support from vzctl and can use "raw
>>>>> vzctl" with some lightweight manuals from my repo:
>>>>> https://github.com/pavel-odintsov/OpenVZ_ZFS/blob/master/OpenVZ_containers_on_zfs_filesystem.md
>>>>>
>>>>> I collected all useful information here
>>>>> https://github.com/pavel-odintsov/OpenVZ_ZFS
>>>>>
>>>>> Stay tuned! Join to us!
>>>>>
>>>>> --
>>>>> Sincerely yours, Pavel Odintsov
>>>>> _______________________________________________
>>>>> Users mailing list
>>>>> Users at openvz.org
>>>>> https://lists.openvz.org/mailman/listinfo/users
>>>>
>>>>
>>>> _______________________________________________
>>>> Users mailing list
>>>> Users at openvz.org
>>>> https://lists.openvz.org/mailman/listinfo/users
>>>
>>>
>>>
>>> --
>>> Sincerely yours, Pavel Odintsov
>>>
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>>
>>
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>
>
>
> --
> Sincerely yours, Pavel Odintsov



-- 
Sincerely yours, Pavel Odintsov



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