[openstack-dev] [Cinder][Manila]share or volume's size unit

Duncan Thomas duncan.thomas at gmail.com
Tue Apr 11 13:25:27 UTC 2017


Changing the size to a float creates rounding issues, and means
changes to the db, the api definition, and changes to every single
client and client library out there, for very little gain.

On 10 April 2017 at 04:41, jun zhong <jun.zhongjun2 at gmail.com> wrote:
> I agree with you extend might be one way to solve the problem.
>
> By the way, How about another way that we could import volume
> size with float value? such as: 2.5G, 3.4G?
>
> Did community consider about it in the begin?
>
>
> 2017-04-07 20:16 GMT+08:00 Duncan Thomas <duncan.thomas at gmail.com>:
>>
>> Cinder will store the volume as 1G in the database (and quota) even if
>> the volume is only 500M. It will stay as 500M when it is attached
>> though. It's a side effect of importing volumes, but that's usually a
>> pretty uncommon thing to do, so shouldn't affect many people or cause
>> a huge amount of trouble.
>>
>> There are also backends that allocate in units greater than 1G, and so
>> sometimes give you slightly bigger volumes than you asked for. Cinder
>> doesn't not go out if its way to support this; again the database and
>> quota will reflect what you asked for, the attached volume will be a
>> slightly different size.
>>
>> In your case, extend might be one way to solve the problem, if you
>> backend supports it. I'm not certain what will happen if you ask
>> cinder to extend to 1G a volume it already thinks is 1G... if it
>> doesn't work, please file a bug.
>>
>> On 7 April 2017 at 09:01, jun zhong <jun.zhongjun2 at gmail.com> wrote:
>> > Hi guys,
>> >
>> > We know the share's size unit is in gigabiyte in manila, and volume's
>> > size
>> > unit is also in gigabiyte in cinder, But there is a question that the
>> > size
>> > is not exactly after we migrate tradition enviroment to OpenStack.
>> > For example:
>> > 1.There is original volume(vol_1) with 500MB size in tradition
>> > enviroment
>> > 2.We want to use openstack to manage this volume(vol_1)
>> > 3.We can only use 1GB volume to manage the original volume(vol_1),
>> > because
>> > the cinder volume size can not support 500MB.
>> > How to deal with this? Could we set the volume or share's unit to float
>> > or
>> > something else? or add new unit MB? or just extend the original volume
>> > size?
>> >
>> >
>> > Thanks
>> > jun
>> >
>> >
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>>
>>
>>
>> --
>> Duncan Thomas
>>
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-- 
Duncan Thomas



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