[ovirt-users] shared storage with iscsi

[Dan Yasny]

On Thu, Dec 4, 2014 at 12:54 PM, mad Engineer <themadengin33r at gmail.com>
wrote:

> sorry i am wrong its the data domain that stores virtual disk images,I
> have no idea how ovirt shares block device across hosts.Looks like i
> need to try that for understanding how its implemented.In case of
> vmware they uses vmfs file system for sharing block device among
> hosts.I currently have no issues with my NFS shared storage so dont
> have any plan to use iscsi,but just curious how the implementation
> is.In my existing non ovirt environment,SAN block devices is exported
> and its shared using GFS.Is ovirt using any simillar method to achieve
> shared block device.
>
>
oVirt uses a different approach altogether (this is why it can scale to
clusters with hundreds of hosts, unlike vmware). The idea is pretty simple
1. format the shared block storage with LVM
2. Every VM disk image is an LV
3. manage host access to separate LVs using simple lvchange.

Of course there's much more to the way this is implemented, but very simply
-  no two hosts have write access to the same LV, unless it is specified as
a shared disk, so no clustered FS is needed, no scsi reservations are
needed and this concept scales, unlike vmfs, gfs, and other such systems.




>
>
> On Thu, Dec 4, 2014 at 9:10 PM, mad Engineer <themadengin33r at gmail.com>
> wrote:
> > Thanks Gianluca,it says only NFS is supported as export domain.I
> > believe export domain is the one i am currently using for live
> > migrating vms across hosts.So iscsi is not supported,please correct me
> > if i am wrong.Thanks for your help
> >
> > On Thu, Dec 4, 2014 at 9:00 PM, Gianluca Cecchi
> > <gianluca.cecchi at gmail.com> wrote:
> >> On Thu, Dec 4, 2014 at 4:23 PM, mad Engineer <themadengin33r at gmail.com>
> >> wrote:
> >>>
> >>> Thanks Maor,in non ovirt kvm setup i use GFS2 to make the block device
> >>> shareable across multiple hosts.Could you tell me how is it achieved
> >>> in ovirt.
> >>>
> >>> Regards
> >>>
> >>
> >> First step the admin guide:
> >> http://www.ovirt.org/OVirt_Administration_Guide
> >>
> >> and in particular the Storage chapter and the related iSCSI part:
> >> http://www.ovirt.org/OVirt_Administration_Guide#.E2.81.A0Storage
> >>
> >> Also, for multipath in case you need it:
> >> http://www.ovirt.org/Feature/iSCSI-Multipath
> >>
> >> HIH,
> >> Gianluca
> _______________________________________________
> Users mailing list
> Users at ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ovirt.org/pipermail/users/attachments/20141204/19490127/attachment-0001.html>