Live migration on Cloudmin

Hi guys !

We have just installed Cloudmin on a Virtual machine and added a Xen host.

Is there any possibility to create live migration feature? We are currently just getting to know Cloudmin before putting it in production. However, we will put our own Storage supplying disk space for XEN hosts.
Therefore we are thinks about live migration as some customers will be able to get a service with such feature and pay for it. We are evaluating using a virtual server on top of a XEN CentOS based OS, to host a 20.000 users website.

This client would not like to have its website down, while we move his virtual machine from one physical host to another, for maintenance reasons or any other…

So we are eager to explore this possibility.



I did speak with one of their developers about it and its something they are going to put on the roadmap. Its also not like you couldnt manually run the command to do the migration as well.

Live migration is definitely in the plans for Cloudmin, for virtualization technologies that support it (like Xen).

Hi Joe,

We are definitely going to test this. We have developed our own storage system, and we are building a lab for this.

The main ideia is in fact very simple:
Two Xen physical hosts with CentOS 53, with shared storage via AoE on our Storage system, using GFS2.

I’lll let you know how it went.


When will this feature be available? And will Cloudmin be able to automatically switch a XEN VPS from a failed host to a standby host, in the case where the VPS is installed on shared iSCSI storage?

When will this feature be available?

I’m pretty sure Jamie mentioned it being underway or finished last time we had a status meeting. So, it’s probably gonna be in the next release.

And will Cloudmin be able to automatically switch a XEN VPS from a failed host to a standby host, in the case where the VPS is installed on shared iSCSI storage?

I’m not sure about this one. Live migrations require both instances to be “live” at the time of migration, but there probably is a mechanism for handling failover with some grace, which we’ll need to look into a bit. But, it’s definitely in the plans…robustness against failure is a big part of the benefit of cloud computing, so it’ll definitely be part of the product in the not too distant future.

Hi, we are also very interested in using Cloudmin with Xen, especially for the Fault Tolerance and High Availability features.

Some questions:

  1. We are thinking of using 3x Sun X2270 8 core 32GB machines and 1x Sun 7110 for storage. All the machines will run OpenSolaris. Does Cloudmin support the Xen running on OpenSolaris (
  2. How is Fault Tolerance and High Availability implemented (Xen & Remus)? If it is not available now, when and how will it be available?
  3. Can Cloudmin manage both zones and Xen instances at the same time?
  4. The licenses (10 or 50 servers) are based on running servers, it doesn’t count standby machines?



I’m interested to find out how the high availability feature is coming along. Can you please update me on this?

Hi Martin,

Some answers to your questions :

  1. Cloudmin doesn’t yet support Xen on Solaris, only on Linux. It does support Solaris Zones though.

  2. We haven’t looked into this yet, sorry.

  3. Yes, it can.

  4. The system counts for licenses only count virtual systems (Xen guests, Solaris Zones), not standby host systems. By virtual systems are counted even if they are not running.

Hi Jamie,

  1. Do you think it will be available soon, as far as I know it is just Xen on OpenSolaris. Are there any real Linux depended features which are not available on OpenSolaris or implemented differently?

  2. Mmmm I haven’t tested it yet but I think it is really great. Do you think it can run besides Cloudmin?

  3. Ok great!

  4. Ok.



Technically, I think it wouldn’t be too hard to support Xen on OpenSolaris, assuming that the tools and config files are still the same as Linux. The only feature that would be hard to support is LVM, which Cloudmin can use for Xen instances on Linux to improve performance (but isn’t mandatory).

Would you be hosting OpenSolaris Xen guests, or Linux?

If we can replace LVM with ZFS on OpenSolaris that would be great! Most of guest will be OpenSolaris but some will be Linux (Debian or CentOS).


Is ZFS really comparable to LVM though? Cloudmin using LVM on Linux to provide a block device for Xen instances to use for their filesystems… and my understanding was that ZFS provides only filesystems and not block devices.

I think you need zfs zvol

Please have a look at

Here the create an UFS filesystem on top of a ZFS volume.