I updated my main NAS today and unfortunately found that none of my virtual machines running on it would start. Unfortunately my main DNS server and filtering software was running on that.
A quick internet search found this:
Users upgrading to DSM 7.4.1-90080 have reported that Virtual Machine Manager (VMM) fails to initialize correctly, specifically causing the virtual network switch and storage pool to remain inactive. This issue was observed on models like the DS723+ running VMM version 2.7.0-12229, where virtual machines lost network connectivity and the system reported errors despite the underlying binaries being present.
The root cause was identified as a version incompatibility, with Synology support suggesting that the stable package branch was insufficient for the new DSM release. The resolution involved manually installing the VMM 2.8.0-12322 beta package. After installing this beta version and recreating the virtual machine configuration, network and storage functionality was restored.
- Symptom: Virtual network switch and storage pool fail to initialize; VMs lose connectivity.
- Affected Version: VMM 2.7.0-12229 on DSM 7.4.1-90080.
- Fix: Install VMM 2.8.0-12322 (Beta) and reconfigure the virtual machine.
- Warning: Ensure you have backups, as DSM 7.4.1 does not allow downgrading to previous versions.
First issue the beta was not available just an error message, then I remembered my DNS would be in fall back mode and some things might not be available. So I quickly pointed the NAS at an alternative and then beta software was available. I updated my virtual machine manager fixed the issues that caused and could then bring back up my virtual servers.
Bad testing from Synology but I suppose as this was a security update they may have had to rush it out. But some notes on the documentation would have been nice.