openstack team mailing list archive

[John Griffith <john.griffith@xxxxxxxxxxxxx>]

On Tue, Apr 30, 2013 at 9:44 AM, Sylvain Bauza
<sylvain.bauza@xxxxxxxxxxxx>wrote:

>  Indeed. There is room for improvement : should the 2 disks be RAID1 or
> parts of the same VG, as said ?
>
> As it is recommended hardware, it would be interesting to know which kind
> of setup with 2 SATA disks is optimal ?
>
> Of course, it does depend a lot of the usage : if you need to boot from
> volume, I would say having 2 physical PVs is better, but if you need to
> store critical data, then the RAID one is fine.
>
> -Sylvain
>
> Le 30/04/2013 14:35, Alexandre De Carvalho a écrit :
>
> Here the link :
> http://docs.openstack.org/trunk/openstack-compute/admin/content/compute-system-requirements.html
>
>  regards,
> Alexandre
>
> 2013/4/30 Razique Mahroua <razique.mahroua@xxxxxxxxx>
>
>> Hi,
>> can you provide us the link ?
>> I think that means create an LVM VG made of two disks (so two PV) that
>> you will call "nova-volume"
>> Regards,
>>
>>  *Razique Mahroua** - **Nuage & Co*
>> razique.mahroua@xxxxxxxxx
>> Tel : +33 9 72 37 94 15 <%2B33%209%2072%2037%2094%2015>
>>
>>
>>  Le 30 avr. 2013 à 09:49, Alexandre De Carvalho <
>> alexandre7.decarvalho@xxxxxxxxx> a écrit :
>>
>>   Hi everyone !
>>
>>  I found these ones in the documentation : "Volume storage: two disks
>> with 2 TB (SATA) for volumes attached to the compute nodes". And I don't
>> understand this sentence. Someone can explain to me this sentence, please ?
>>
>>  Thanks !
>>
>>  Have a good day !
>>
>>  --
>> regards,
>> Alexandre
>>
>>
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>
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> Hi Sylvain,

This doc is a bit outdated and references Nova Volumes etc, however the
problem I think you're having is that it makes some assumptions regarding
knowledge of how all the components tie together and what they do.  They're
simply guidelines for possible configurations, however given the
flexibility of OpenStack and the numerous use cases I've always thought
this was sort of a difficult task (recommended hardware configs).

That being said, the Volume Group and disk portion of that doc that's being
discussed is in relation to your block-storage through Cinder.  This is the
back-end storage that you're configuring Cinder to use.  The preference
regarding RAID, Size etc are completely up to you, but you can make some of
those decisions based upon how you intend to use your OpenStack deployment.

For example you can just take any free disks/partitions on your Cinder
node, create one big LVM VG out of them (cinder-volumes) and the default
Cinder set up would then allocate space from this VG any time you do a
"cinder create".  The recommendations in the doc are geared toward what
would typically be required to have a functional setup, the size,
configuration and type of disks you use is going to vary depending upon how
many tenants you plan to have, how much block storage you suspect they'll
deploy and what kind of performance they're going to require.

The other thing to keep in mind is OpenStack is fully scale-out, so you can
start with something and as you need more storage for Cinder you can add
Cinder nodes with more disks/VG's.

I hope that helps.

John