[Users] Q on ovirt datacentre and host storage types

[Oved Ourfalli]

----- Original Message -----
> From: "Xiaofan" <xiaofanw at gmail.com>
> To: "Deepak C Shetty" <deepakcs at linux.vnet.ibm.com>
> Cc: users at ovirt.org
> Sent: Wednesday, February 29, 2012 2:18:03 PM
> Subject: Re: [Users] Q on ovirt datacentre and host storage types
> 
> 2012/2/29 Deepak C Shetty <deepakcs at linux.vnet.ibm.com>:
> > Hi, got few basic Qs in my mind. Appreciate a response.
> >
> > 1) Why is it that the data domains must be of the same type as that
> > of
> > datacentre ? What is the goal behind having
> > this constraint ? It seems useful to have a datacentre w/o having
> > any
> > storage restrictions.. i should be able to add
> > hosts w/o worrying abt the storage types... why is it not so...
> > looking to
> > understand the reason behind this design
> > decision.
> 
> vdsm has no such restriction. But spm works not properly with mixture
> storage types.
> For example, say NFS is master domain, and there is also an iscsi
> domain in pool,
> in this situation, the size of inbox/outbox in NFS domain is not
> right, which will cause mailbox exception,
> 
> 
> >
> > 2) If i have a set of host systems all connected to shared FC
> > storage, is
> > there a way for me to configure LUNs
> > exclusively for each host, meaning have ability to control what LUN
> > each
> > hosts sees ? Can this be done using oVirt today ? My understanding
> > is that
> > this cannot be done via ovirt, zoning of LUNs to host has to be
> > done
> > separately and not via ovirt, is that correct ?
> >
If I understood you correctly that is indeed not part of ovirt.
You can put different LUNs in different data centers, but that won't mean a host in a cluster in one DC won't have access to a LUN defined on another DC (it won't have this access through ovirt, but this access will still be available if it was allowed in the storage controller management).

All the hosts in clusters of a specific data center need access to all its storage domains.
So you'd probably want to allow not only a host but a set of hosts, to access the LUN which the storage domains resides on.
Same for NFS exports.

> > 3) If i have to create and run 1000 VMs (say), how can i automate
> > that using
> > ovirt, what is the best way to do that ?
> >
Depends on the scenario. If you are talking about stateless VMs, based on a template, you can use VM Pools.
We are also working on supporting pre-started VMs (see feature page in http://ovirt.org/wiki/Features/PrestartedVm), that will enable you to set a number on that VM pool which says how many VMs you would like to be up from the pool (I think the feature is already pushed, but not sure about that).

If you want them to be separate, then IMO the best way to do so is to use the either the ovirt-CLI or the ovirt-SDK (again, depends on the exact scenario). Using it you can create VMs, run them, stop them and etc....

Details on that can be found in:
www.ovirt.org/wiki/CLI
www.ovirt.org/wiki/SDK

Hope it helps,
Oved
> > thanx,
> > deepak
> >
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