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Lesson 5 Enabling swap space
Objective Enable swap space.

Enabling swap Space

Swapping uses space on a hard disk as an extension of a computer's RAM. By utilizing swap, the operating system pretends that more RAM is available than the machine actually contains.
Swapping: Swapping uses space on a hard disk as an extension a computer\'s RAM. By utilizing swap, the operating system pretends that more RAM is available than the machine actually contains. The oldest files in RAM are "swapped out" to the swap partition until they are needed so that other data can be "swapped in" to RAM.
Your swap should be about three times your RAM, or 256MB, whichever is smaller. You should add more swap as needed, but only if adding RAM isn't an option. If your system has multiple drives, set up a swap partition on each disk. The system views all swap space the same, but when it reads and writes to the swap space, the multiple hard disks allow parallel accesses, increasing performance. However, Linux limits you to eight swap partitions, which means you can't put a swap partition on more than eight hard drives.
Execute the following steps to create a swap partition:
  1. Set up the partition table and add a swap partition (or create a swap file instead) using either the fdisk or cfdisk utility.
  2. Reboot the system.
  3. Create the swap partition using mkswap.
  4. Add an entry for the swap to /etc/fstab.
  5. Activate the swap partition or file using swapon -a.
  6. Check the swap partition's status using swapon -s.

The following Simulation steps you through the process of adding additional swap space.
add swap space
The next lesson explains how to add new drives.

Implementing Swap Space

Before moving on to the next lesson, click the Exercise link to check your understanding of how to implement swap space.
Implementing Swap Space