[one-users] Two System Datafiles in the same cluster
Oriol Martí
omarti at cesca.cat
Tue Dec 18 01:47:16 PST 2012
Yes, I think that your disk speed it doesn't depend on the image
datastore type but on the system datastore type.
This is caused because all the images are copied to your default system
datastore and the VM's run from there. Then, if you want different disk
speed you need different system datafiles, but I don't know how you can
specify a different destination datastore for a disk or for a vm.
Does anybody know if I'm right and how to specify this? Maybe the
solution is to create 2 clusters, one with the local system datastore by
default and the other one with the NFS system datastore. But in this
case I'll need to have the images duplicated in two image datastores and
I think that this is not a good solution.
Thanks!
On 12/18/2012 10:23 AM, André Monteiro wrote:
> Hi Oriol,
> I guess you're right, I had a few problems with disk speed (small
> block size) and I tested other disk:
> - mounted the disk on /mnt/new_disk
> - copied the image.raw and image.qcow2 to new disk
> - created new Datastore (ID=100) and new symbolic link on
> .../datastores/100 pointing to /mnt/new_disk
> - registered new images on Opennebula specifying datastore 100
> - updated template
> - instantiated new VMs
> This allowed me to test the new disk with better results, but I guess
> it would be extremelly useful to input on REQUIREMENTS var the wanted
> datastore.
>
> --
> André Monteiro
>
>
>
>
> On Tue, Dec 18, 2012 at 9:09 AM, Oriol Martí <omarti at cesca.cat
> <mailto:omarti at cesca.cat>> wrote:
>
> 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 <mailto:omarti at cesca.cat>>
> To: "Gary S. Cuozzo" <gary at isgsoftware.net
> <mailto:gary at isgsoftware.net>>
> Cc: "Users OpenNebula" <users at lists.opennebula.org
> <mailto: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
> <mailto:omarti at cesca.cat>>
> To: users at lists.opennebula.org
> <mailto: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!
>
>
>
>
> --
>
> ......................................................................
> __
> / / Oriol Martí Bonvehí
> C E / S / C A Administrador de Sistemes
> /_/ Centre de Supercomputació de Catalunya
>
> Gran Capità, 2-4 (Edifici Nexus) · 08034 Barcelona
> T. 93 551 6212 · F. 93 205 6979 · omarti at cesca.cat
> <mailto:omarti at cesca.cat>
> ......................................................................
>
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