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How to set up swap on Linux cloud server
- PHPzforward
- 2023-05-18 23:55:521975browse
Step one: Confirm the status of swap
Use the following command to check the memory status:
free -m
If the result shows that swap is 0, it means that swap does not exist and you need to create swap.
total used free shared buffers cached Mem: 1840 1614 226 15 36 1340 -/+ buffers/cache: 238 1602 Swap: 0 0 0
Or you can use this command to view it. If no results are output, swap does not exist.
swapon -s
Step 2: Create swap
We use the following command to create a swap file with a size of 2GB.
dd if=/dev/zero of=/swapfile count=2048 bs=1M
The output results are as follows:
2048+0 records in 2048+0 records out 2147483648 bytes (2.1 GB) copied, 10.5356 s, 204 MB/s
Step 3: Activate swap
swap will not be automatically recognized by default. We need to set appropriate permissions before it can be used normally. Execute the following command to set the permissions of the swap file to 600, which means it can be read and written by the root user.
chmod 600 /swapfile
Activate swap:
mkswap /swapfile
The output results are as follows:
Setting up swapspace version 1, size = 2097148 KiB no label, UUID=ff3fc469-9c4b-4913-b653-ec53d6460d0e
Step 4: Enable swap
Execute the following command to enable swap
swapon /swapfile
By default, the swap file will not be automatically started with the system, so it needs to be written to the file system.
vi /etc/fstab
Add the following code at the end:
/swapfile none swap sw 0 0
After saving with the :wq command, swap will be started with the system.
Finally, we can use the free command to confirm whether swap is set successfully.
free -m
The output results are as follows. You can see that swap is no longer 0, indicating that swap has been set successfully.
total used free shared buffers cached Mem: 1840 1754 86 16 23 1519 -/+ buffers/cache: 210 1630 Swap: 2047 0 2047
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