SvSAN - Citrix Hypervisor (Xen) – StorMagic Support

This article is intended for administrators wishing to potentially leverage SvSAN with Citrix Hypervisor or the open source version.

Audience: Administrators Product: SvSAN Platform: Citrix Hypervisor • XCP-ng Topic: Shared Storage • High Availability

https://www.citrix.com/en-gb/products/citrix-hypervisor/

https://xcp-ng.org/

SvSAN with Citrix Hypervisor

Expand the sections below for information regarding the use of StorMagic SvSAN with Citrix Hypervisor or the open source version.

StorMagic SvSAN

StorMagic SvSAN is a virtual SAN – a software-defined solution designed to run on two or more servers and deliver highly available shared storage.

SvSAN simplifies your IT infrastructure. It eliminates the need for a physical SAN, enabling hyperconvergence by virtualizing the internal compute and storage of any x86 server and presenting it via a hypervisor as shared storage.

Citrix Hypervisor

Citrix Hypervisor provides a highly reliable and secure open source virtualization platform for cloud, server and desktop virtualization infrastructures.

Explanation

Citrix hypervisor is a minimum 3x node solution in order to enable/provide compute quorum.

https://discussions.citrix.com/topic/414084-2-node-cluster-on-version-81-reboots-if-i-re-enable-ha/

"A 2-node HA configuration is not officially supported by Citrix and will lead to problems (the so-called "split brain" issue, when communication between the two nodes fails and it's unclear which should become the master)."

Citrix Hypervisor also stores cluster configuration, when enabling HA, on the shared storage.

These requirements mean that SvSAN CANNOT run in a hyperconverged configuration with Citrix Hypervisor, or must utilize UPS and is unable to tolerate a cluster down power failure scenario..

This is due to a chicken and egg situation.

That being a cluster down environment power failure scenario, whereby the VSAs can't start without the cluster and the cluster can't start due to the cluster state being on the shared storage, that isn't available.

SvSAN can, however, provide shared storage if running off this cluster in a configuration similar to the below:

Or if a single node failure protection only is required and UPS is in place to ensure a cluster down won't occur.

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