SWAP Space Management in Linux


A SWAP space is an area of a disk which can be used for memory management subsystem. Swap space are used to supplement the system RAM by holding inactive pages of memory.

What is Logical Volume Management in Linux

How to create a swap space: 

To create a swap space, needs to do three things:
1. Create partition.
2. Set the type of the partition as 82 Linux Swap.
3. Format the type signature on the device.

How to create SWAP space

Create a 500 MiB SPAP space:
1. Create a 500 MiB partition on /dev/vdb on Linux swap.
            # fdisk /dev/vdb
2. Print the table, and then create a new partition that is 500 MiB in size.
            # p
            # n
            # p
            # 1
            # +500M         (Enter size we want to create SWAP Space)
            # p
3. Set new created partition to type Linux swap.
            # t
            # 1
            # L
            # 82
            # p
4. Save the partition table changes.
            # w
5. Run the partprobe to make the kernel aware of the partition table change.
            # partprobe
6. Initiate the newly created partition as swap space.
            # mkswap /dev/vdb1
7. Enable newly created swap space.
   7.1 To See created swap space is enable use following command.
            # free 
   7.2 Enable created space as a SWAP space.
            # swapon /dev/vdb1
   7.3 Verify that the newly created swap space is available.
            # free
8. Configure new swap space so that it is enable at boot.
    8.1 Determine UUID of the new swap partition on the first disk.
            # blkid /dev/vdb1
    8.2 Add an entry to /etc/fstab
            # vim /etc/fstab
            Paste here UUID        swap    swap    defaults           0          0         
    8.3 Test enabling the swap space using the entry.
            # swapon –a
    8.4 Verify that the new swap space was enabled.
            # free

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