When working with virtual VPS/VDS servers, failures and errors are possible, which most often occur as a result of incorrect user actions. For example, when making changes or updating applications, it is easy to damage the file system and lose important data.
What is a snapshot
This is a quick snapshot of a virtual server that is used for backing up and later restoring data, as well as for easily deploying information to new servers. You get an accurate image of the virtual machine at a specific point in time. Any subsequent changes to the virtual machine will not affect this snapshot and you can always revert to it. This is convenient, for example, when developing before a controversial commit or when experimenting with operating system settings.
What data can be saved with a server snapshot
- Contents of files and directories.
- Components of the operating system and installed applications.
- Information on disks, in RAM and databases.
- Server configuration and settings.
VPS server snapshot is a complete copy of the virtual server file system. It can be used to fully restore the state of the server, which will continue to work from the moment of creating such a snapshot.
How to make a snapshot of the server
There are two ways to create snapshots.
- Creating a snapshot without stopping the server. Files are copied while the server is running, which may result in data loss. The method is suitable for simple systems.
- Creating a snapshot with stopping the server. Recommended for servers where files and databases change frequently.
When and how snapshots are used
The snapshot is used before starting technical work, updates, inspection or testing. The current state of the system is saved in a special file. If the changes are successful, they are saved and merged with the existing snapshot.
You can create a sequential or branching chronological chain of images during copying.
- If you delete one of the snapshots, all unsaved changes made after its creation will be lost.
- When restoring from an intermediate snapshot, its contents will be merged with the next link, and when canceling the last one, with the current state of the virtual machine.
- The snapshot chain has no impact on data security.
Warning! Without control over the automatic creation of snapshots, their sizes may exceed the file system limit, which will negatively affect the performance of the VPS/VDS server.
Backup and snapshot - are there any differences
Although at first glance both technologies seem similar, they have significant differences. A backup is a duplicate of data. It is created to save all files, or the most important or frequently changing files, so that the information can be restored if necessary. A snapshot is a snapshot of the state of a virtual machine. A snapshot can also be used to revert the system to a previous configuration.
If it is necessary to save data for a long period of time, it is better to use a backup, which can then be placed outside the VPS/VDS server. To fix the temporary state of the system and successfully roll back to it, it is better to use snapshots, which are displayed in the log in a special format and stored on the main disk. The optimal option is to use both tools.
Summary
Snapshots greatly simplify the work with virtual servers and cloud hosting. Regular rollbacks allow you to test critical applications and prevent possible software failures.
