Hi,<br><br>On Thu, Oct 13, 2011 at 5:54 PM, Fabian Wenk <span dir="ltr"><<a href="mailto:fabian@wenks.ch">fabian@wenks.ch</a>></span> wrote:<br><br><blockquote style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;" class="gmail_quote">
I hope this helps and my information are correct, if not, could somebody from OpenNebula please correct me.<br></blockquote>
<br>Thank you for your great contributions to the list!<br><br>I'd like to add that we tried to summarize the implications of the shared [1] and non-shared [2] approaches in the documentation, let us know if there are any big gaps we forgot about.<br>
<br>Regards.<br><br>[1] <a href="http://opennebula.org/documentation:rel3.0:sfs#considerations_limitations">http://opennebula.org/documentation:rel3.0:sfs#considerations_limitations</a><br>[2] <a href="http://opennebula.org/documentation:rel3.0:nsfs#considerations_limitations">http://opennebula.org/documentation:rel3.0:nsfs#considerations_limitations</a><br clear="all">
<span style="border-collapse:collapse;color:rgb(136, 136, 136);font-family:arial,sans-serif;font-size:13px">--<br>Carlos Martín, MSc</span><font color="#888888"><br>Project Engineer</font><br><span style="border-collapse:collapse;color:rgb(136, 136, 136);font-family:arial, sans-serif;font-size:13px"><span style="background-color:rgb(255, 255, 204);color:rgb(34, 34, 34);background-repeat:initial initial">OpenNebula</span> - The Open Source Toolkit for Cloud Computing<br>
<a href="http://www.opennebula.org/" style="color:rgb(42, 93, 176)" target="_blank">www.<span style="background-color:rgb(255, 255, 204);color:rgb(34, 34, 34);background-repeat:initial initial">OpenNebula</span>.org</a> | <a href="mailto:cmartin@opennebula.org" style="color:rgb(42, 93, 176)" target="_blank">cmartin@<span style="background-color:rgb(255, 255, 204);color:rgb(34, 34, 34);background-repeat:initial initial">opennebula</span>.org</a></span><br>
<br><br><div class="gmail_quote">On Thu, Oct 13, 2011 at 5:54 PM, Fabian Wenk <span dir="ltr"><<a href="mailto:fabian@wenks.ch">fabian@wenks.ch</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hello Humberto<div class="im"><br>
<br>
On <a href="tel:13.10.2011" value="+13102011" target="_blank">13.10.2011</a> 11:03, Humberto N. Castejon Martinez wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Reading the Opennebula documentation, I believe there are two things I have<br>
to deal with:<br>
<br>
1) The image repository, and whether it is shared or not between the<br>
front-end and the workers<br>
</blockquote>
<br></div>
I have some persistent Images which are used for "persistent" VMs. I have the images folder shared with NFS and I use tm_nfs. When starting a VM with a persistent images, it creates only a soft link in VM_DIR which points to the image in the images folder. If you want to have copied the persistent image into the VM_DIR on the cluster node, you would need tm_ssh. But then on startup the whole image will be copied to the cluster node into VM_DIR and on shutdown it will be copied back to the images folder.<div class="im">
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
2) The<VM_DIR>, that contains deployment files, etc for the VMs running on<br>
a worker. This directory may or not be shared between the front-end and the<br>
workers, but it should always be shared between the workers if we want live<br>
migration, right?<br>
</blockquote>
<br></div>
If you use tm_ssh you do not need to share this, if you use tm_nfs, you need to have it shared. The same with the images folder. For live migration you need a shared images folder and VM_DIR.<div class="im"><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Some of the questions I have are these (sorry if some of them seem stupid<br>
:-)):<br>
</blockquote>
<br></div>
They are not stupid, It took me some time to try out and see through how this things works, and so I had to change my setup a few times until OpenNebula an I were happy.<div class="im"><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
- What are the implications of sharing or not the image repository between<br>
the front-end and the workers (apart from the need to transfer images to the<br>
worker nodes in the latter case)?<br>
</blockquote>
<br></div>
See above.<div class="im"><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
- What are the implications of sharing or not the<VM_DIR> between the<br>
front-end and the workers?<br>
</blockquote>
<br></div>
Also above.<div class="im"><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
- Can I use ZFS or MooseFs and still be able to live migrate VMs?<br>
</blockquote>
<br></div>
MooseFS [1] is a fault tolerant, network distributed file system (eg. over several servers). I do not know if ZFS can do this. MooseFS is similar like NFS, only that the data are distributed over several servers (including your local server). I guess live migration should work.<br>
<br>
[1] <a href="http://www.moosefs.org/" target="_blank">http://www.moosefs.org/</a><div class="im"><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
- Will the<VM_DIR> always hold a (copy of a) VM image for every VM running<br>
on a worker? Must the<VM-DIR> be in the local hard drive of a worker or may<br>
it reside on an external shared storage?<br>
</blockquote>
<br></div>
See above, if used with tm_nfs, it is on a external shared storage (NFS server). When used with tm_ssh, it is on the local disk and all images (public or persistent) will be copied in full through ssh.<div class="im"><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
I guess two factors i should also consider when choosing a solution are the<br>
following, right?<br>
<br>
- The speed of transferring VM images<br>
- The speed of cloning VM images<br>
</blockquote>
<br></div>
Yes. Access to a persistent image through NFS only transfers the data needed, cloning always creates a full copy. When you use tm_ssh, the image will always be copied in full through ssh (which also gives some CPU overhead on the front end and cluster node).<br>
<br>
I hope this helps and my information are correct, if not, could somebody from OpenNebula please correct me.<br>
<br>
<br>
bye<br>
Fabian<br>
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</blockquote></div><br>