Comment créer un espace de swap dans le système d'exploitation Linux

Échanger de l'espace sous Linux: Qu'est-ce que c'est et comment le créer sur CentOS

L'espace d'échange sous Linux fonctionne de la même manière que la mémoire virtuelle sous Windows, agissant comme une extension de la RAM physique lorsque le système manque de mémoire. Instead of allowing the operating system to crash or hang when RAM is fully utilized, swap space temporarily holds inactive data by using part of the hard drive. While swap is much slower than RAM (even on SSDs or NVMe drives), it plays a crucial role in maintaining system stability under high memory pressure.

How Much Swap Space Should You Allocate?

Là’s no strict rule, but here are some common recommendations:

• If your system has 16 Go de RAM, and you’re not limited by disk space, allocate 8–16 GB of swap.
• SSDs or NVMe drives offer better performance, but are still slower than RAM, so don’t expect RAM-level performance from swap.

Preliminary Steps Before Proceeding

• Backup your data before making any system-level changes.
• Ensure you have root access to the system.
• If you’re using a server, connect via SSH (voir « How to Connect via SSH »).

Creating Swap Space on CentOS

1. Log in as Root Access your CentOS system as the root user or with sudo privileges.
2. Create Swap File Use the following command to allocate 8GB of disk space to swap:

dd if=/dev/zero of=/swapspace bs=1024 count=8388608

Explanation:

Hébergement Web WordPress

À partir de 3,99 $/mois

Acheter maintenant

• 8 GB = 8192 Mo
• 8192 × 1024 = 8,388,608 Ko
• bs=1024: sets the block size
• count=8388608: number of blocks to write

3. Set Ownership to Root

chown root:root /swapspace

4. Set Permissions

chmod 0600 /swapspace

5. Format as Swap

mkswap /swapspace

6. Activate Swap

swapon /swapspace

7. Make Swap Persistent Open the /etc/fstab file:

nano /etc/fstab

If nano is not installed, courir: yum install nano

Add the following line at the end of the file:

/swapspace none swap sw 0 0

Reboot the System

Now reboot to ensure changes are applied:

reboot

Verify Swap Activation

Après le redémarrage, use the following command to check swap:

Serveur VPS pas cher

À partir de 2,99 $/mois

Acheter maintenant

free -m

You will see the RAM and swap usage stats.

Need Expert Help?

Si tu’d prefer to leave server management to the pros, purchase a managed VPS. Hosting providers like Mizbanfa offer full server support including swap configuration, surveillance, et optimisation.