Optimal Swap Partition Sizing: Modern Guidelines for Linux Servers with 8GB RAM


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The traditional "double your RAM" rule for swap space originated when systems typically had limited physical memory (often ≤2GB). Modern systems with 8GB+ RAM require more nuanced considerations:


# View current memory and swap usage:
free -h
# Sample output for 8GB system:
              total        used        free
Mem:           7.7Gi       2.1Gi       5.6Gi
Swap:          2.0Gi       0.0Gi       2.0Gi

For your 8GB server, consider these factors:

  • Hibernation support: If needed, swap = RAM size + 10% (≈9GB)
  • Standard server use: 4GB swap (50% of RAM) is typically sufficient
  • Memory-intensive workloads: Monitor usage first before allocating

Here's how to adjust swap space post-installation:


# Create a 4GB swap file (alternative to partition):
sudo fallocate -l 4G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
# Make permanent by adding to /etc/fstab:
/swapfile none swap sw 0 0

Modern Linux kernels (4.0+) handle memory more efficiently. Key metrics to monitor:


# Check swapiness (default 60):
cat /proc/sys/vm/swappiness
# Check memory pressure:
vmstat 1 5
# Check OOM killer activity:
dmesg | grep oom

Consider 16GB swap if:

  • Running memory-hungry applications (e.g., large Java services)
  • Using memory overcommit features
  • Expecting rare memory spikes

The old rule of thumb suggesting swap space should be double your RAM originated from an era when physical memory was scarce and expensive. Today, with modern systems boasting ample RAM and advanced memory management techniques, this guideline requires reevaluation.

For a server with 8GB RAM, here are current best practices:

  • Minimum: Equal to RAM size (8GB) for hibernation support
  • Recommended: Between 25-50% of RAM (2-4GB) for servers
  • Maximum: Rarely exceeds RAM size for performance reasons

Excessive swap space can actually harm performance:

# Check current swap usage
free -h
# Sample output:
#               total        used        free      shared  buff/cache   available
# Mem:           7.7G        1.2G        5.8G         16M        696M        6.2G
# Swap:          8.0G          0B        8.0G

For an 8GB server running Ubuntu 22.04:

# Create a 4GB swap file instead of partition
sudo fallocate -l 4G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
# Make permanent
echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstab

Consider larger swap in these scenarios:

  • Memory-intensive applications with unpredictable spikes
  • Servers with limited RAM upgrade options
  • Systems requiring hibernation capability

Regularly monitor swap usage to right-size your configuration:

# Check swappiness value (default 60)
cat /proc/sys/vm/swappiness
# Temporarily set to more conservative value
sudo sysctl vm.swappiness=30

Remember that swap is not a substitute for adequate physical memory. For most modern servers with 8GB RAM, a 4GB swap space provides the best balance between safety and performance.