[one-users] Two System Datafiles in the same cluster

[Gary S. Cuozzo]

Hi Oriol,
I have deployed my own DS & TM drivers for my NFS & LocalFS datastores.  What they do is utilize mount points outside of the ONE directory and just symlink from the system datastore into the appropriate filesystem.  For example:
/export/local/image1.img  (local disk mounted here)
/export/san1/image2.img  (NFS mounted from SAN1)
/export/san2/image3.img  (NFS mounted from SAN2)

The drivers symlink into the system datastore to each of those images.

This way, I am able to select the best of both worlds depending on the application.  Shared storage with live migrations, etc.  Or, local storage with high performance disk I/O.

Thanks,
gary

----- Original Message -----
From: "Oriol Martí" <omarti at cesca.cat>
To: "Gary S. Cuozzo" <gary at isgsoftware.net>
Cc: "Users OpenNebula" <users at lists.opennebula.org>
Sent: Tuesday, December 18, 2012 4:09:32 AM
Subject: Re: [one-users] Two System Datafiles in the same cluster

Hi Gary,

I've read the docs, but I think I'm not understanding something, when 
you create vm's all the images are copied in the 
/var/lib/one/datastores/0, then all your virtual machines are running 
from an NFS system datastore and it's impossible to run the virtual 
machines from local storage....
Have you tried to create virtual machines from different datastores and 
see if the disk speed is really different?

On 12/17/2012 06:37 PM, Gary S. Cuozzo wrote:
> I do exactly what you reference below, use NFS for shared storage and also localfs for high performance local storage.  But, I only have 1 system datastore.  When you use shared storage such as NFS or iSCSI, the system datastore also has to be shared.  I think the system datastore is typically datastore ID 0.  That's what it is in my system as it's created by ONE.
>
> In your case, you will need to share the system DS to each host in the cluster.  For example, I have /var/lib/one/datastores/0 NFS exported from ONE controller to each vm host and mounted there in the same place.
>
> Then, you just use each other DS as you wish and ONE handles copying, linking, etc as needed.
>
> Hope that makes some sense.  Read up on the storage docs, they are very good as describing all this.
>
> gary
>
>
> ----- Original Message -----
> From: "Oriol Martí" <omarti at cesca.cat>
> To: "Gary S. Cuozzo" <gary at isgsoftware.net>
> Cc: "Users OpenNebula" <users at lists.opennebula.org>
> Sent: Monday, December 17, 2012 12:17:47 PM
> Subject: Re: [one-users] Two System Datafiles in the same cluster
>
> Hi Gary,
>
> thank you for your fast response,
> my idea is to have an NFS and a local datastore, which are system
> datastores, to store the images of the running vms. Then you can create
> vms with faster disk (local) or slower disk (NFS). I've tried to have
> two systems datastores in the same cluster and it's possible.
>   From what I understood, when you create a vm, the image is copied from
> the image datastore to the default system datastore, which you define in
> the cluster as SYSTEM_DS. I don't know if its possible to create a vm in
> a different datastore than the cluster's default.
>
> I don't know if I'm missing something about the copy process or
> something.... Basically I would like to decide, when I create a vm, to
> give it faster or slower disk depending on what I need. In my point of
> view I think that if you use image datastores faster, you only will take
> advantage of the speed when is copying, one time copied it's going to be
> slower if its copied in a slower NFS datastore.
>
> Best regards,
>
>
> On 12/17/2012 04:42 PM, Gary S. Cuozzo wrote:
>> Hello Oriol,
>> I don't think you can have more than one system datastore, but I could be wrong about that.  But, unless I misunderstand your goal, I don't think you need to have more than one.  You should simply be able to define 2 datastores and associate each with the cluster.  I have a similar setup to what you describe, I have a cluster that has 2 different NFS datastores, a local file datastore, and an iSCSI datastore.  I can use images from any/all datastores in a single vm (though I actually don't).
>>
>> Hope that helps,
>> gary
>>
>>
>> ----- Original Message -----
>> From: "Oriol Martí" <omarti at cesca.cat>
>> To: users at lists.opennebula.org
>> Sent: Monday, December 17, 2012 9:53:43 AM
>> Subject: [one-users] Two System Datafiles in the same cluster
>>
>> Hi,
>>
>> somebody knows if it is possible to have two system datastores in a cluster and create VM in the same host but in different datastores?
>> I've my default SYSTEM_DS="101" in the cluster, I've tried to add to the MV template to change the datastore which the vm is created:
>> REQUIREMENTS= "DATASTORE_ID = \"103\""
>> (I don't know if this is correct)
>>     
>> But the VM does not boot, and is in pending state. Somebody know if is possible or I have to create two clusters one with the datastore 101 and another one with the datastore 103?
>>
>> My idea is to have one cluster with one NFS datastore and another local-file datastore.
>>
>> Thanks!
>>
>


-- 

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   C E / S / C A      Administrador de Sistemes
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