<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Dec 4, 2014 at 12:54 PM, mad Engineer <span dir="ltr"><<a href="mailto:themadengin33r@gmail.com" target="_blank">themadengin33r@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">sorry i am wrong its the data domain that stores virtual disk images,I<br>
have no idea how ovirt shares block device across hosts.Looks like i<br>
need to try that for understanding how its implemented.In case of<br>
vmware they uses vmfs file system for sharing block device among<br>
hosts.I currently have no issues with my NFS shared storage so dont<br>
have any plan to use iscsi,but just curious how the implementation<br>
is.In my existing non ovirt environment,SAN block devices is exported<br>
and its shared using GFS.Is ovirt using any simillar method to achieve<br>
shared block device.<br>
<br></blockquote><div><br></div><div>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</div><div>1. format the shared block storage with LVM</div><div>2. Every VM disk image is an LV</div><div>3. manage host access to separate LVs using simple lvchange.</div><div><br></div><div>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.</div><div><br></div><div><br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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On Thu, Dec 4, 2014 at 9:10 PM, mad Engineer <<a href="mailto:themadengin33r@gmail.com">themadengin33r@gmail.com</a>> wrote:<br>
> Thanks Gianluca,it says only NFS is supported as export domain.I<br>
> believe export domain is the one i am currently using for live<br>
> migrating vms across hosts.So iscsi is not supported,please correct me<br>
> if i am wrong.Thanks for your help<br>
><br>
> On Thu, Dec 4, 2014 at 9:00 PM, Gianluca Cecchi<br>
> <<a href="mailto:gianluca.cecchi@gmail.com">gianluca.cecchi@gmail.com</a>> wrote:<br>
>> On Thu, Dec 4, 2014 at 4:23 PM, mad Engineer <<a href="mailto:themadengin33r@gmail.com">themadengin33r@gmail.com</a>><br>
>> wrote:<br>
>>><br>
>>> Thanks Maor,in non ovirt kvm setup i use GFS2 to make the block device<br>
>>> shareable across multiple hosts.Could you tell me how is it achieved<br>
>>> in ovirt.<br>
>>><br>
>>> Regards<br>
>>><br>
>><br>
>> First step the admin guide:<br>
>> <a href="http://www.ovirt.org/OVirt_Administration_Guide" target="_blank">http://www.ovirt.org/OVirt_Administration_Guide</a><br>
>><br>
>> and in particular the Storage chapter and the related iSCSI part:<br>
>> <a href="http://www.ovirt.org/OVirt_Administration_Guide#.E2.81.A0Storage" target="_blank">http://www.ovirt.org/OVirt_Administration_Guide#.E2.81.A0Storage</a><br>
>><br>
>> Also, for multipath in case you need it:<br>
>> <a href="http://www.ovirt.org/Feature/iSCSI-Multipath" target="_blank">http://www.ovirt.org/Feature/iSCSI-Multipath</a><br>
>><br>
>> HIH,<br>
>> Gianluca<br>
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</blockquote></div><br></div></div>