How to Optimize Proxmox

This guide shows you how to optimize your Proxmox VE installation after setup. With the right settings, VMs and containers run more stably, backups become faster and the host consumes fewer resources.

1. Optimize the Host System

Disable unnecessary services

Proxmox comes with many services you may not need. Check the status and disable unused services:

systemctl list-units --type=service --state=running

If you don't use Ceph, you can disable Ceph services. Verify that you really don't use Ceph before doing so.

Adjust swappiness

Proxmox should use as little swap as possible – VMs and containers need RAM. Set swappiness to 10:

echo "vm.swappiness = 10" >> /etc/sysctl.conf
sysctl -p

Apply updates regularly

apt update && apt dist-upgrade -y

Run updates regularly, preferably outside peak hours and after taking a snapshot of your most important VMs.

2. Optimize Storage

Limit ZFS ARC size

If you use ZFS, the Adaptive Replacement Cache (ARC) reserves a lot of RAM by default. Limit it so enough memory remains for VMs:

echo "options zfs zfs_arc_max=4294967296" >> /etc/modprobe.d/zfs.conf
update-initramfs -u

The value 4294967296 equals 4 GB – adjust it to your available RAM (approx. 25–50% of total RAM).

Use thin provisioning

Create VM disks as thin provisioned when your storage supports it. A 100 GB disk then only uses the space actually written initially.

Enable discard/TRIM

Enable Discard on SSD-based storage and set scsi0: ...,discard=on in the VM. This keeps SSD performance stable long-term.

3. VM and Container Performance

Install QEMU Guest Agent

Install the QEMU Guest Agent in every VM. It enables clean shutdowns, better backups and accurate RAM reporting:

apt install qemu-guest-agent -y
systemctl enable --now qemu-guest-agent

In Proxmox enable it under VM → Options → QEMU Guest Agent.

CPU type and cores

Set the CPU type to host for maximum performance (pass-through of host CPU features). Distribute vCPU cores sensibly – don't exceed physical cores without good reason.

Use ballooning carefully

Memory ballooning can redistribute RAM dynamically but may cause performance fluctuations. For production game servers or databases, fixed RAM allocation is usually better.

Use VirtIO drivers

Always use VirtIO for disks and network instead of IDE or E1000 – this reduces CPU load and significantly increases throughput.

4. Optimize Network

Check bridge configuration

The default bridge vmbr0 should be on your fastest network card. Check the configuration:

cat /etc/network/interfaces

Use VLANs for separation

Separate management, VM and backup traffic via VLANs. This improves security and prevents network bottlenecks.

5. Optimize Backups

Plan backup windows

Run backups at night or during low-traffic periods. Staggered backups (VMs one after another instead of simultaneously) reduce I/O spikes.

Choose snapshot mode

With the QEMU Guest Agent installed, use snapshot mode for consistent backups of running VMs.

Integrate Proxmox Backup Server

For larger environments a dedicated Proxmox Backup Server (PBS) is worthwhile. Deduplication saves massive storage space and speeds up incremental backups.

6. Monitoring and Maintenance

Keep an eye on resources

Use the Proxmox dashboard and optionally tools like Grafana or Prometheus to monitor CPU, RAM, I/O and network.

Clean up old backups and snapshots

pvesm list local

Delete unneeded backups and snapshots regularly – otherwise they waste storage space.

Rotate logs

Make sure logrotate is active so system and Proxmox logs don't fill up your disk.

7. Quick Checklist

1. Set swappiness to 10
2. Limit ZFS ARC size (if using ZFS)
3. Enable thin provisioning and discard for SSDs
4. Install QEMU Guest Agent in all VMs
5. Use CPU type host and VirtIO for disk/network
6. Run backups during off-peaks with snapshot mode
7. Apply updates regularly and delete old backups

More guides on installation and backup can be found in the left navigation under Proxmox.