Reasonable use of virtual resources in the operation and maintenance of overseas cloud servers can ensure the core functions of system stability. The virtual memory is used to expand the disk space and alleviate the insufficient physical memory. However, the virtual memory setup process must consider system requirements and hardware characteristics. The following describes the setting methods and optimization strategies based on different operating systems and scenarios.

1. Set the virtual memory of the Linux system

Linux uses Swap partitions or Swap files to implement virtual memory, which is suitable for cloud servers with small physical memory (such as models with 1GB memory).

To create a Swap file, create a dedicated directory:

mkdir /swap && cd /swap  

Generate a Swap file and use the dd command to create a file of a specified size (for example, 2GB) :

dd if=/dev/zero of=/swap/swapfile bs=4k count=512000  

Parameter Description: bs=4k Indicates that the block size is 4KB. count=512000 Indicates the total number of blocks (4KB 512000 = 2GB).

Set permissions and format:

chmod 600 /swap/swapfile  
mkswap /swap/swapfile  

To activate Swap:

swapon /swap/swapfile  

For persistent configuration, edit the /etc/fstab file and add:

/swap/swapfile swap swap defaults 0 0  

The Swap automatically takes effect after the restart.

Optimization suggestion

Swap size: It is recommended to set the swap size to 12 times the physical memory. If the memory size is greater than 4GB, the swap size can be reduced appropriately.

Performance tuning: Store Swap files on independent disks or high-speed SSDS to avoid I/O competition with system disks.

2. Set the virtual memory of the Windows operating system

Windows manages virtual memory through a paging file (Pagefile.sys), which is suitable for servers running large applications or multitasking.

Manual configuration procedure. Open system Settings by right clicking on "This Computer" → "Properties" → "Advanced System Settings" → "Advanced" TAB → "Settings" button in the "Performance" area.

To adjust virtual memory, select the "Change" button in the "Advanced" TAB → "Virtual Memory" area. Uncheck automatically manage paging file sizes for all drives. Select a non-system disk (such as disk D), select Custom Size, and enter the initial value and maximum value (for example, if the physical memory is 16GB, the initial value is 24GB, and the maximum value is 48GB).

Restart takes effect. After the modification, restart the server for the configuration to take effect.

Optimization suggestion

Disk selection: High-speed SSDS or independent disks are preferred to store paging files to reduce I/O latency.

Dynamic adjustment: Avoids fixed size, allows the system to scale according to demand, and prevents bursts of low memory.

3.cross-platform precautions and optimization strategy

Resource monitoring. Periodically use free h (Linux) or Task Manager (Windows) to check memory and Swap usage.

If the virtual memory is frequently used, the physical memory is insufficient. Therefore, upgrade the memory specifications.

Avoid over-reliance on virtual memory. The disk I/O speed of virtual memory is much lower than that of physical memory, which may cause performance bottlenecks in high-load scenarios. For example, expand the physical memory of the database server first.

Security and stability Linux ensures that the Swap file permission is 600 to prevent unauthorized access. Windows avoid disabling paging files, which may cause a system crash.

Service provider features adaptation:

Some overseas cloud service providers may have restrictions on the use of Swap, and you need to consult official documents to adjust the policy.

4. special scenario solutions

Memory-optimized instances (such as AWS R5 or Azure E series) are recommended for highly concurrent applications to reduce reliance on virtual memory. Combined with containerization techniques such as Docker, limit the memory usage of a single container to avoid global resource exhaustion.

During temporary task processing, you can temporarily increase the Swap size for short-term tasks with high memory, such as compilation and rendering, and restore the default configuration after the task is complete.

In the hybrid storage architecture, Swap files can be deployed on NVMe SSDS or Ramdisks to improve read/write efficiency.

5. Troubleshooting of common problems

Swap does not take effect:

Check for /etc/fstab format errors (Linux) or paging file path permissions (Windows).

Performance degradation:

Use iostat (Linux) or Performance Monitor (Windows) to analyze disk I/O bottlenecks and consider migrating Swap to high-speed disks.

The above is that we can flexibly configure virtual memory according to the actual load of overseas cloud servers, balance performance and own business costs. Virtual memory is a temporary solution. Upgrading physical memory or selecting a higher configuration instance is the basic optimization path in scenarios with long-term high load.