# Enabling Swap Space

Swap space is necessary for the database components to function properly.

# Swap Size

For production servers, set swap to 50% of the physical memory.

For testing systems, set swap to 100% of the physical memory.

Check available memory:

free

             total       used       free     shared    buffers     cached
Mem:       1922136    1274196     647940         32      92508     315664
-/+ buffers/cache:     866024    1056112
Swap:      2064380      31016    2033364

# Enabling Swap

The following instructions describe how to create swap without restarting the server.

Create 1 GB file (1M * 1024). Increase count= as appropriate.

sudo dd if=/dev/zero of=/swapfile bs=1M count=1024

Set permissions and configure the swap file.

sudo chmod 0600 /swapfile

sudo mkswap /swapfile

Enable swap.

sudo swapon /swapfile

Enable swap on boot.

sudo echo "/swapfile swap swap defaults 0 0" >> /etc/fstab

Verify that the swap is enabled.

free

The output must contain a row with Swap total not equal to zero.

             total       used       free     shared    buffers     cached
Mem:       7697000    6104904    1592096         32      86628    3062424
-/+ buffers/cache:    2955852    4741148
Swap:      1023996          0    1023996