VMware VM Performance Tuner

A tool to optimize VMware virtual machines for maximum performance using industry-standard best practices.

Features

• GRUB Boot Parameters: Optimizes kernel boot parameters for VMware environments
• Sysctl Tuning: Configures kernel parameters for memory, network, and I/O performance
• Filesystem Optimization: Updates /etc/fstab with performance-oriented mount options
• I/O Scheduler: Configures optimal I/O schedulers for virtual disks
• Network Tuning: Optimizes network interface settings for vmxnet3 drivers
• Automatic Backups: All changes are backed up with rollback capability
• Dry Run Mode: Preview changes before applying them

Requirements

• Linux system running on VMware (tested on Debian/Ubuntu)
• Root/sudo access
• Go 1.21 or higher (for building from source)

Installation

Build from Source

# Clone repository
git clone https://github.com/dtouzeau/vmware-tuner.git
cd /vmware-tuner
go mod download
go build -o vmware-tuner
sudo mv vmware-tuner /usr/local/bin/

Quick Build

git clone https://github.com/dtouzeau/vmware-tuner.git
go build -ldflags="-s -w" -o vmware-tuner

Usage

Apply All Optimizations

sudo vmware-tuner

Dry Run (Preview Changes)

sudo vmware-tuner --dry-run

Show Current Configuration

sudo vmware-tuner show

Verify Tuning Status

sudo vmware-tuner verify

Selective Tuning

Skip specific modules:

# Skip GRUB tuning (no reboot required)
sudo vmware-tuner --no-grub

# Skip network tuning
sudo vmware-tuner --no-network

# Combine multiple flags
sudo vmware-tuner --no-grub --no-network

What Gets Optimized

1. GRUB Boot Parameters

• elevator=noop - Optimal I/O scheduler for VMs
• transparent_hugepage=madvise - Reduce memory fragmentation
• clocksource=tsc - Use TSC for timekeeping
• intel_idle.max_cstate=0 - Disable deep C-states for lower latency
• And more...

2. Sysctl Parameters

• vm.swappiness=10 - Reduce swap usage
• vm.dirty_ratio=15 - Optimize dirty page flushing
• net.ipv4.tcp_congestion_control=bbr - Better TCP throughput
• Enhanced network buffer sizes
• File system optimizations

3. Filesystem Mount Options

• noatime - Don't update access times (30% less I/O)
• nodiratime - Don't update directory access times
• commit=60 - Reduce sync frequency
• Removes discard option (not supported by VMware)

4. I/O Scheduler

• Sets none/noop scheduler for all virtual disks
• Increases queue depth to 256
• Optimizes read-ahead to 256KB

5. Network Configuration

• Increases ring buffers (RX/TX: 4096)
• Enables hardware offloading (GSO, GRO, TSO)
• Optimizes interrupt coalescing

Backup and Rollback

All changes are backed up to /root/.vmware-tuner-backups/<timestamp>/

Manual Rollback

cd /root/.vmware-tuner-backups/<timestamp>
sudo bash rollback.sh

Restore Individual Files

cd /root/.vmware-tuner-backups/<timestamp>
sudo cp fstab /etc/fstab
sudo cp grub /etc/default/grub
sudo update-grub

Reboot Requirement

Changes that require a reboot:

• GRUB boot parameters
• Filesystem mount options (if remount fails)

Changes applied immediately:

• Sysctl parameters
• I/O scheduler (for current devices)
• Network settings

Performance Impact

Expected improvements:

• I/O Performance: 15-30% improvement for sequential operations
• Network Throughput: 10-20% improvement for high-bandwidth workloads
• Latency: Reduced CPU idle latency, faster response times
• Memory: Better cache retention, reduced swapping

Safety

• All changes are reversible
• Dry run mode available
• Automatic backups created
• VMware detection (warns if not running on VMware)
• Root check (prevents accidental runs)

Compatibility

Tested on:

• Debian 12 (Bookworm)
• Ubuntu 22.04/24.04
• VMware ESXi 6.x/7.x/8.x

Should work on any modern Linux distribution running on VMware.

Troubleshooting

BBR Congestion Control Not Available

If you see warnings about BBR:

# Check available congestion control algorithms
sysctl net.ipv4.tcp_available_congestion_control

# Load BBR module (if available)
sudo modprobe tcp_bbr
echo "tcp_bbr" | sudo tee -a /etc/modules

Remount Failed

If filesystem remount fails, changes will take effect on next boot.

Service Failed to Start

Network tuning service may fail if interfaces are not ready. Changes will apply on next boot.

Advanced Usage

Custom Configuration

Edit the source files to customize:

• grub.go - Boot parameters
• sysctl.go - Kernel parameters
• fstab.go - Mount options
• scheduler.go - I/O settings
• network.go - Network settings

Then rebuild:

go build -o vmware-tuner

License

This tool is provided as-is for VMware VM optimization purposes.

Credits

Developed for optimizing VMware virtual machines based on industry best practices and VMware performance tuning guides.