viktor/infra
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

scripts: per-VM I/O cap script — apply-mbps-caps.sh

Browse source 
Idempotent qm-set script for the per-VM I/O caps on the PVE host's sdc
thin pool (2026-05-26 session, beads code-9v2j). Caps protect each
Linux VM's share of sdc so a runaway workload (e.g. the 2026-05-23/26
alloy IO storm — memory id=2726) cannot saturate the disk for everyone.

Was sitting in /tmp on PVE — moving the source under version control
and installing to /usr/local/bin/ alongside the other PVE operational
scripts (nfs-mirror, daily-backup, offsite-sync-backup; pattern from
memory id=609). Survives PVE host reboots; safe to re-run on any node
rebuild to restore the caps.

VMIDs covered (Linux only — pfSense 101 and Windows10 300 skipped):
  102 devvm 60/60   103 home-assistant 40/40   200 k8s-master 100/60
  201 k8s-node1 150/120   202 k8s-node2 150/120   203 k8s-node3 150/120
  204 k8s-node4 150/120   220 docker-registry 40/40
This commit is contained in:
Viktor Barzin 2026-05-26 08:06:15 +00:00
parent 44c3770a5c
commit 232409e798
1 changed files with 47 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

47
scripts/apply-mbps-caps.sh Executable file
View file

@ -0,0 +1,47 @@
#!/usr/bin/env bash
# Apply per-VM I/O caps via qm set on the PVE host.
# - Reads each VM's current boot-disk options
# - Appends mbps_rd=<N>,mbps_wr=<N>
# - Re-applies via qm set (live, no reboot needed)
# - Verifies with qm config | grep mbps
set -euo pipefail
# vmid:disk_slot:mbps_rd:mbps_wr (Linux VMs only — skipping 101 pfsense BSD, 300 Windows)
TARGETS=(
"102:scsi0:60:60" # devvm
"103:sata0:40:40" # home-assistant
"200:scsi0:100:60" # k8s-master (alloy storm origin — firmest clip)
"201:scsi1:150:120" # k8s-node1 (GPU + many CSI disks; boots from scsi1)
"202:scsi0:150:120" # k8s-node2
"203:scsi0:150:120" # k8s-node3
"204:scsi0:150:120" # k8s-node4 (currently doing write recovery)
"220:scsi0:40:40" # docker-registry
)
for spec in "${TARGETS[@]}"; do
IFS=: read -r vmid slot rd wr <<<"$spec"
printf '\n=== VMID %s slot=%s rd=%s MB/s wr=%s MB/s ===\n' "$vmid" "$slot" "$rd" "$wr"
current=$(qm config "$vmid" | awk -v s="$slot:" '$1==s {sub(/^[^ ]+ /, ""); print; exit}')
if [[ -z "$current" ]]; then
echo " ERROR: could not read $slot for vmid $vmid — skipping"
continue
fi
# Strip any existing mbps_rd / mbps_wr from the current string (idempotent)
cleaned=$(echo "$current" | sed -E 's/,mbps_rd=[0-9]+//g; s/,mbps_wr=[0-9]+//g')
newvalue="${cleaned},mbps_rd=${rd},mbps_wr=${wr}"
echo " before: $current"
echo " after: $newvalue"
qm set "$vmid" "--$slot" "$newvalue"
echo " verify: $(qm config "$vmid" | awk -v s="$slot:" '$1==s {print; exit}')"
done
echo
echo "=== Final verification — mbps on all targets ==="
for spec in "${TARGETS[@]}"; do
IFS=: read -r vmid slot _ _ <<<"$spec"
echo "vmid $vmid: $(qm config "$vmid" | awk -v s="$slot:" '$1==s {print; exit}')"
done