Swap (swap space) is an important mechanism used in Linux systems to extend physical memory, when there is not enough physical memory, the system will swap inactive memory pages into Swap space. The following is the complete procedure for configuring Swap in Ubuntu:<\/p>\n\n\n\n
First verify that Swap is enabled on your system:<\/p>\n\n\n\n
sudo swapon --show<\/code><\/pre>\n\n\n\n\n- no output<\/strong>: Indicates that there is currently no active Swap space<\/li>\n\n\n\n
- exporting<\/strong>: Display information about enabled Swap partitions\/files<\/li>\n<\/ul>\n\n\n\n
2. Creating a Swap file<\/h2>\n\n\n\n2.1 Creating a Swap File<\/h3>\n\n\n\n
Recommended fallocate<\/code> Quick Create (use if not available) dd<\/code>):<\/p>\n\n\n\n# Method 1: Use fallocate (recommended, faster)\nsudo fallocate -l 2G \/swapfile # Creating a 2GB Swap file\n# Method 2: Use dd (better compatibility)\nsudo dd if=\/dev\/zero of=\/swapfile bs=1G count=2 status=progress<\/code><\/pre>\n\n\n\n2.2 Setting file permissions<\/h3>\n\n\n\n
Make sure that only the root user has access:<\/p>\n\n\n\n
sudo chmod 600 \/swapfile<\/code><\/pre>\n\n\n\n2.3 Formatting as a Swap Region<\/h3>\n\n\n\nsudo mkswap \/swapfile<\/code><\/pre>\n\n\n\nExample output:<\/p>\n\n\n\n
Setting up swapspace version 1, size = 2 GiB (2147479552 bytes) no label, UUID=xxxx-xxxx-xxxx-xxxx-xxxx<\/code><\/pre>\n\n\n\n2.4 Enabling Swap Files<\/h3>\n\n\n\nsudo swapon \/swapfile<\/code><\/pre>\n\n\n\n3. Verify Swap enabled status<\/h2>\n\n\n\nsudo swapon --show<\/code><\/pre>\n\n\n\nExample output:<\/p>\n\n\n\n
NAME TYPE SIZE USED PRIO\n\/swapfile file 2G 0B -2<\/code><\/pre>\n\n\n\nor using free-h<\/code> View:<\/p>\n\n\n\nfree-h<\/code><\/pre>\n\n\n\nExample output:<\/p>\n\n\n\n
total used free shared buff\/cache availableMem: 3.8G 1.2G 100M 200M 2.5G 2.2GSwap: 2.0G 0B 2.0G<\/code><\/pre>\n\n\n\n4. Persistent configurations (power-on auto-mount)<\/h2>\n\n\n\n4.1 Editing an fstab file<\/h3>\n\n\n\nsudo nano \/etc\/fstab<\/code><\/pre>\n\n\n\n4.2 Adding Swap Configuration Items<\/h3>\n\n\n\n
Add at the end of the document:<\/p>\n\n\n\n
\/swapfile none swap sw 0 0<\/code><\/pre>\n\n\n\nor configuration with prioritization (optional):<\/p>\n\n\n\n
\/swapfile none swap sw,pri=10 0 0<\/code><\/pre>\n\n\n\n\npri=10<\/code>: Sets the Swap priority (the higher the value the higher the priority)<\/li>\n\n\n\n- Save to exit:
Ctrl+X<\/code>\u00a0\u2192\u00a0Y<\/code>\u00a0\u2192\u00a0Enter<\/code><\/li>\n<\/ul>\n\n\n\n5. Configure Swappiness parameters (optional)<\/h2>\n\n\n\n
The Swappiness value controls the system's tendency to use Swap:<\/p>\n\n\n\n
\n- 0-100<\/strong>: The smaller the value, the more you tend to use physical memory.<\/li>\n\n\n\n
- default value<\/strong>:: 60<\/li>\n<\/ul>\n\n\n\n
5.1 Viewing Current Values<\/h3>\n\n\n\ncat \/proc\/sys\/vm\/swappiness<\/code><\/pre>\n\n\n\n5.2 Temporary modifications (reboot disabled)<\/h3>\n\n\n\nsudo sysctl vm.swappiness=10<\/code><\/pre>\n\n\n\n5.3 Permanent modifications<\/h3>\n\n\n\n
Edit the configuration file:<\/p>\n\n\n\n
sudo nano \/etc\/sysctl.conf<\/code><\/pre>\n\n\n\nAdd at the end of the document:<\/p>\n\n\n\n
vm.swappiness=10<\/code><\/pre>\n\n\n\nApply the configuration after saving the exit:<\/p>\n\n\n\n
sudo sysctl -p<\/code><\/pre>\n\n\n\n6. Cautions<\/h2>\n\n\n\n\n- File Size Selection<\/strong>::\n
\n- Physical Memory \u2264 2GB: recommended Swap = 2 \u00d7 Physical Memory<\/li>\n\n\n\n
- Physical Memory 2-8GB: recommended Swap = Physical Memory<\/li>\n\n\n\n
- Physical memory \u2265 8GB: recommended Swap = 4-8GB (or as needed)<\/li>\n<\/ul>\n<\/li>\n\n\n\n
- Performance considerations<\/strong>::\n
\n- Swap files underperform Swap partitions<\/li>\n\n\n\n
- Swap on SSDs is faster than HDDs<\/li>\n\n\n\n
- Consider using\u00a0
zswap<\/code>\u00a0maybe\u00a0zram<\/code>\u00a0Improve performance<\/li>\n<\/ul>\n<\/li>\n\n\n\n- Secure deletion of Swap<\/strong>(if required):
sudo swapoff \/swapfile <\/code>
sudo rm \/swapfile <\/code>
sudo nano \/etc\/fstab # Delete corresponding line<\/code><\/li>\n\n\n\n- Monitoring Swap Usage<\/strong>::
vmstat 1 5 # Refresh every second, 5 times in total<\/code>
top # Press M to sort by memory<\/code>
htop # More intuitive monitoring tool (installation required)<\/code><\/li>\n<\/ol>\n\n\n\nBy following these steps, you can successfully configure and enable Swap space on your Ubuntu system and adjust system parameters as needed for optimal performance.<\/p>","protected":false},"excerpt":{"rendered":"
Swap\uff08\u4ea4\u6362\u7a7a\u95f4\uff09\u662f Linux \u7cfb\u7edf\u4e2d\u7528\u4e8e\u6269\u5c55\u7269\u7406\u5185\u5b58\u7684\u91cd\u8981\u673a\u5236\uff0c\u5f53\u7269\u7406\u5185\u5b58\u4e0d\u8db3\u65f6\uff0c\u7cfb\u7edf\u4f1a\u5c06\u4e0d\u6d3b\u8dc3\u7684\u5185\u5b58\u9875 […]<\/p>","protected":false},"author":1,"featured_media":1321,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"image","meta":{"footnotes":""},"categories":[275],"tags":[299,300,336,372,391],"class_list":["post-857","post","type-post","status-publish","format-image","has-post-thumbnail","hentry","category-linux","tag-swap","tag-ubuntu","tag-performance","tag-system","tag-computer","post_format-post-format-image"],"_links":{"self":[{"href":"https:\/\/www.livetops.com\/en\/wp-json\/wp\/v2\/posts\/857","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.livetops.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.livetops.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.livetops.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.livetops.com\/en\/wp-json\/wp\/v2\/comments?post=857"}],"version-history":[{"count":1,"href":"https:\/\/www.livetops.com\/en\/wp-json\/wp\/v2\/posts\/857\/revisions"}],"predecessor-version":[{"id":1392,"href":"https:\/\/www.livetops.com\/en\/wp-json\/wp\/v2\/posts\/857\/revisions\/1392"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.livetops.com\/en\/wp-json\/wp\/v2\/media\/1321"}],"wp:attachment":[{"href":"https:\/\/www.livetops.com\/en\/wp-json\/wp\/v2\/media?parent=857"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.livetops.com\/en\/wp-json\/wp\/v2\/categories?post=857"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.livetops.com\/en\/wp-json\/wp\/v2\/tags?post=857"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}