How to create a Cluster with XEN?

natucoqui used Ask the Experts™
I have two Dell poweredge 2950 with 16g og memory and 4 disk of 140g on raid 1"two miror", attached with two HBA on each node to a EMC cx-3-80 with shared configuration for cluster purpose, what the best configuration to cluster xen on centos?, or guide to make it append.
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You might want to re-post this in the VMware forum rather than the VMS/OpenVMS forum.
Distinguished Expert 2017

You can cluster the centos
Xen cluster how to with ubuntu I think you can use it as a reference for apply it in Centos:

You do not need to use drbd since you have a shared storage EMC CX3-80.


Hi Arnold, what do you recommend if I have two hba on each server, I use power path from emc, or you recommend me another open source solution?
Distinguished Expert 2017
Presumably you are not clustering the centos systems.
you are looking at the setup where you have two XEN virtualization servers running and would like the VMs to be transitioned between the two hosts as needed.

The powerpath is fine for the the problem is how you would manage the XEN's reposiory.
I.e. would you use a LUN for each virtualmachine such that the LUn can be transitioned from one xen host to another.
The example in the links deal with using the local disks instead of a shared storage that you have.
drbd is a disk level replication process (some what like rsync is for file level replication) that cold potentially be setup such that the second RAID 1 pair of 146GB is synchronized between the two servers.

You already have a shared storage so data replication is not what you are looking at.

The issue whether you want the server load-balance the VMs or have the XEN app in failover.
cluster centos servers with EMC shared storage as a resource and xen only runs on the active node. In this case I think during the transition from the active node to the formerly passive node, all VMs will be shutdown until XEN starts up on the new active node and then starts all the VMs.

The other option is to run XEN on both centos servers. and XEN configured for transitioning VMs between them.
i.e. if XEN on host1 is being shutdown the guest VMs that are runningon that host are transitioned in realtime to the XEN app on host2.

It sounds as though you are testing things out, I would suggest follow the instructions for the XEN cluster how to initially with the DRBD setup.
This will provide you with the working knowledge.  Then you would be in a better position to know how the XEN real-time of VM transitions works and will guide you on how to setup/handle the shared storage to deal.
i.e. the first RAID 1 volume on each server will have the OS/XEN installed the second RAID 1 Volume will be the drbd "shared storage"  At a later point you can add/incorporate the EMC shared storage as another resource where XEN can store its VMs.

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