Posts
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Xenorchestra V6 issue
Team,
I am facing issue while giving extra storage when i select any Installation source. But when i select storage then it allow me to give size.
XO info: Xen Orchestra, commit 91314

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Windows Server 2025 VM randomly freezes/hangs (loss of VNC + RDP + console) on XCP-ng โ reboot required
My Windows Server 2025 Standard VM randomly becomes completely unresponsive. No response via VNC console, RDP, or any network service. The VM shows as "Running" in XO/XCP-ng Center.
RAM/CPU graphs in XO freeze at the last value. No errors or relevant logs in Windows Event Viewer (daemon/kernel), XCP-ng host logs, or hypervisor logs. Only solution is a forced reboot (or power off/on via XO). After reboot, the VM works normally for hours/days until the next freeze.This matches known Windows Server 2025 + Xen issues.
Environment
- Hypervisor: XCP-ng (version: please add yours, e.g. 8.3.x)
- Orchestrator: XO (XOA)
- VM Details (from XO API / XO):
{ "id": "adf48a15-0b02-6fee-21d8-895190077680", "name_label": "<VM name>", "power_state": "Running", "virtualizationMode": "hvm", "os_version": { "name": "Microsoft Windows Server 2025 Standard", "uname": "10.0.26100" }, "CPUs": { "max": 4, "number": 4 }, "memory": { "size": 17179820032 }, "viridian": true, "pvDriversVersion": "9.1.145-77", "pvDriversDetected": true, "managementAgentDetected": true, "management agent": "9.1.145-77", "NIC type": "Realtek RTL8139", "VGA": "cirrus", "boot": { "firmware": "bios", "order": "cd" }, "other": { "base_template_name": "Other install media" } }- Hardware Virtualization: PVHVM with paravirtualization drivers enabled.
- Storage: (please specify: local SR, NFS, iSCSI, etc. + VBD types)
- Network: Realtek RTL8139 (emulated)
Steps Already Taken
- Viridian extensions are enabled (viridian: true).
- Latest XCP-ng Windows PV Drivers + Management Agent 9.1.145-77 installed.
- Windows Server 2025 is fully updated.
- Checked host logs (xl dmesg, journalctl), guest Event Viewer โ nothing at the time of freeze.
- VM uses BIOS boot (not UEFI).
Additional Context
The freeze is completely random (no specific workload, time of day, or high load trigger observed).
Reboot always resolves it temporarily.
Similar reports exist for Windows 11 24H2 / Server 2025 on XCP-ng (Viridian synthetic timer, PV drivers, emulated devices).Questions
Are there any known issues with Realtek RTL8139 NIC on Server 2025? Should I switch to a PV network driver / different emulated NIC?
Any recommendations on VGA (cirrus) or other VM settings?
Should I try forcing a kernel memory dump next time it hangs (xl trigger <domid> nmi)?
Any other diagnostics or logs I should collect?Thanks in advance!
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RE: SR.Scan performance withing XOSTOR
@Pilow does SR.scan checks only keep-alive or do any kind of write operation or anything else?
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RE: GPU Virtualization
@olivierlambert is there any official documentation by your team? Will you guys add this officially in xcp-ng?
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GPU Virtualization
Hi,
I have attached an NVIDIA GPU to my host and completed the initial configuration successfully. The GPU is now visible in Xen Orchestra / XenCenter.
Currently, the GPU is fully assigned (passthrough) to a single virtual machine. However, my requirement is to share or virtualize the same GPU across multiple VMs.
I would like to know:
Is it possible to virtualize or share an NVIDIA GPU among multiple VMs in a Xen/XCP-ng environment?
If yes, what techniques or technologies are available to achieve this (e.g., vGPU, SR-IOV, mediated devices, etc.)?What are the prerequisites and limitations (supported GPU models, drivers, licensing requirements)?
Any guidance or best-practice recommendations would be highly appreciated.
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DHCP Assigned ip is not showing in network interface
My vm gets ip from the dhcp server but in network tab it is not showing the assigned ip?




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RE: How to create xen orchestra plugins
@Ahkh3e How you then imported this in XO?
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RE: How to create xen orchestra plugins
is there any documentation for building the plugin and how to use in XO?
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RE: Oracle 8.10 cloud.init template creation
@AtaxyaNetwork I'm new to Oracle Linux, do you have any minimal guide for the packages and configs for it? I am going with the first one for now. Created Oracle VM via ISO and configured network, storage(lvm), user and root user password. Now I'm inside my VM.
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Oracle 8.10 cloud.init template creation
I want to build
cloud.inittemplate for Oracle-8.10. Is there anyway to do this via Packer or XO? -
RE: Upgrade to XO v5.105 seems broken
@olivierlambert you are not checking the typescript level traces that's why there's no errors happening at your end.
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RE: SQL Database support and XO HA
@olivierlambert PostgreSQL is good at scale, btw I'm opening an issue in the XO repo so that I'll be aware to any action to this feature either now or in future. Thank you.
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RE: SQL Database support and XO HA
@olivierlambert said in SQL Database support and XO HA:
wait for the next major modification
what about XO6 the full revamped version of XO?
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SQL Database support and XO HA
Hello,
As we know, XO uses Redis as its database for data storage. If something goes wrong at the Redis level, everything goes dark. You mentioned that we can back up the XO configuration and re-import it, but thatโs not a complete solution.
If we are fully dependent on XO to manage a large infrastructure, there should be proper persistence at the XO level. Additionally, there should be official documentation on XO HA (High Availability) so that we can implement load balancing and ensure redundancy.

