Duplicator Documentation

Documentation, Reference Materials, and Tutorials for Duplicator

Working With Different Archive Engines

The differences lie in the underlying technologies and methods used for compressing and archiving files. Shell Zip leverages system commands, ZipArchive is a PHP class for zip file manipulation, and DupArchive is a custom engine developed for the Duplicator plugin, catering to its specific needs. The choice of engine can impact factors like speed, compatibility, and functionality within the context of the application using them.

In This Article

Difference Between Each Archive Engine
Managing ZipArchive
Frequently Asked Questions

Difference Between Each Archive Engine

Shell Zip

Shell Zip executes a command to compress the website files and database into a single .zip archive. This method is often quicker and more reliable than using PHP ZipArchive. If this option is available on your system, we suggest selecting Shell Zip.

Shell Zip is accessible with Basic and higher license levels only.

Shell Zip requires the zip and unzip packages to be installed on your server. It also depends on the PHP functions popen and pclose being enabled.

If Shell Zip is disabled, this means one or more of these requirements are missing or disabled on your server. In that case, contact your hosting provider and ask them to install the zip/unzip packages and enable the popen and pclose PHP functions.

ZipArchive

ZipArchive is a PHP class that allows manipulation of Zip archives. It provides a programming interface for creating and extracting zip files directly within PHP scripts. ZipArchive is more portable across different server configurations since it operates at the PHP level, ensuring consistency in zip file creation regardless of the underlying operating system.

DupArchive

DupArchive is a file format that generates an [archive.daf] file, unique to Duplicator. Specifically tailored for Duplicator, this format prioritizes performance and scalability. Budget hosting providers often impose strict timeouts, CPU, and I/O constraints on their servers. DupArchive was crafted to overcome these limitations, enabling users to create larger backups without being hindered by server constraints.

Managing ZipArchive

To create backups using ZipArchive, Duplicator requires the ZipArchive PHP extension to be installed and enabled on your server.

You can easily validate the installation of ZipArchive by checking with phpinfo.

Alternatively, check if ZipArchive is installed from the Duplicator Pro tools page. Go to Duplicator Pro » Tools » General » PHP Information, Scroll to Configure Command, and check if the –enable-zip is enabled:

Note: If you don’t see ‘–enable-zip‘ enabled in the Configure Command section, this means the ZipArchive is not installed or activated. Reach out to your host or server administrator and ask them to enable ZipArchive for you.

Frequently Asked Questions

If Duplicator fails despite host confirmation, what should I do?

Ensure your host is checking the correct version, as there are various ways to perform Zip compression in PHP. Ask them to visit this link for instructions on enabling the Zip Archive class. Note that this extension is typically enabled by default on most major hosting platforms.

Check if Zip extensions are enabled on your computer?

On your computer, ensure that the Zip extensions are enabled for PHP. Check your php.ini file for: On Windows: extension=php_zip.dll
On Mac and Linux: extension=zip.so

Additional References

Also see: How do I do a ‘Manual Extraction’ or run installer without Zip enabled?

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