Re: Two redundant Xen servers with one SAN

[GD <g.d.monnezza@xxxxxxxxxx>]

    Hi.
      In my opinion the goal you wish to achive is not reachable.
      Two identical VM on two different VM can't symultaneously run if
      the root filesystem is shared.
      
      The only way I can imagine is to have pseudo-HA, having a shared
      root filesystem for the two xen host, but only one running the the
      VM.
      When the running xen host goes down, you can (manually or via
      heartbeat script) start the VM(s) on the second xen host.
      Of course, the VM will have a boot-up time and probably a
      filesystem recovery.
      
      If you wish to have a full-HA solution, you have to setup two
      simultaneously running VMs each with its own root filesystem  (and services configuration) on
      the two xen hosts, a shared data filesystem and an external load
      balancing service (HAproxy or NGINX rev proxy) in failover mode.
      
      Hope it helps
      g

On 24/06/21 10:09, mabi wrote:

> Hello,
>
> Is it possible with Xen on Debian 10 to have two Xen servers both directly attached in a redundant way through HBA interfaces to a single SAN?
>
> The goal here would be to achieve higher availability of the Vms in case one Xen server is down for maintenance or because it is defective. This would mean that the the virtual machines can continue to run on the second available Xen server. The SAN would be used to store the virtual machines images directly via LVM I guess.
>
> I did not find any Xen documentation or third-party howtos in order to do that. Does anyone have any pointers to some documentation or hints? or maybe this is simply not possible?
>
> Best regards,
> Mabi
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