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ddotson

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XenServer Disaster Recovery Replication

Hello:

I have a project to roll out a XenServer host.  This will be a stand-alone host; no pool.  For disaster recovery, we have purchased two identical host servers.  One will sit next to the original host, and the other will be off-site.

I need to find a way to get the guests replicated to the DR hosts.  I was looking at Steeleye, but they are no longer developing their product for Xen.  I've found a couple products (Acronis, Alike) that do backups, but not replication.

So - what do you think?  How can I accomplish this?  Can I use something like Alike and make this work?  Can I use the built in stuff to do it?
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ToxicPig
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Is there a possibility of having some kind of shared storage?  The two don't need to be standalone.  The resource pooling, live migration, and local manual failover are all features of the free version of Xenserver.

If not, you can set the VM's to snapshot and export once a night or once a week, and then replicate to the other server.  You would still need some sort of network storage on which to stage the images.

Let me know which road to go down, and I can post a procedure.
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ddotson

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Shared storage isn't an option.  I guess using a NAS device would be the next option.
Actually, as NAS device would work fine, provided it speaks NFS.  Depending on what you have, I wouldn't use it for the production VM's, but it would be fine to stage, back up, and recover your VM's from one server to the other.

If you have a non-low-end NAS, such as one of the entry-level NetApp devices, that would work great even for production VM's.  Your average Western Digital/Seagate/Buffalo device you get from Best Buy would be fine for backups (NFS), but not running VM's.
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Each server has its own local storage (1.25 TB, RAID 5).  I was hoping to replicate the VMs from one host to the other so that each host looked identical.  Only difference is that on the DR hosts, the VMs would be powered down.  We'd only fire up in the event that a host went down.
Honestly, this is the wrong way to go about things.  Better to use storage pooling and live migration.  That being said, you can set up nightly snapshots of the running VMs.  You can then push the exports over to the second server, and import them into that server.  

Caveats:

If your VMs are over about 20GB (actual data size) or so, this may be prohibitively time-consuming and resource-intensive.  Live Migration on shared storage relies on the fact that the actual data does not need to move.  You might want to look into something like OpenFiler if you are cost-concious.

You will need to have some Linux scripting and cronjob experience to set up the replication jobs.  Can give you the commands and where to put them, but you'll need to stitch them into the system.

Let me know if you would like the export/import commands.
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Sorry for the delay on getting back to you.  I've talked to my supervisor and we want to continue.  Can you send me those commands?
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ToxicPig
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Thank you for your help.  This will get us going!