The raw string compare never matched qm config's canonical key order, so
the hourly timer re-issued 'qm set' against every running capped VM,
live-rewriting QEMU throttle state via QMP 24x/day. Implicated in today's
devvm freeze (15:21-16:48 UTC): the guest's disk I/O stalled inside QEMU
(blockstats frozen at 0 while QMP stayed responsive) on the legacy lsi
controller path with no iothread.
Viktor asked to root-cause the freeze before choosing fixes, then approved
mitigating via VM settings: this commit fixes the hourly trigger and
documents the incident; the controller swap (virtio-scsi-single +
iothread=1 + aio=threads) is staged on VM 102 separately, pending his
cold stop/start.
Adds docs/post-mortems/2026-06-11-devvm-qemu-io-stall.md (evidence chain,
ruled-out causes, capture-before-kill autopsy steps) and syncs compute.md
+ proxmox-inventory.md.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
c3a63fcd38