# BackendTester

Before trusting a storage location with your backups, it's essential to verify its reliability. The built-in Storage Testing Tool helps validate your backup destination through comprehensive integrity testing.

The BackendTester binary is called `Duplicati.CommandLine.BackendTester.exe` and `duplicati-backend-tester` on Linux and MacOS. The tool is mostly intended for system administrators that needs to verify a certain storage solution is working as expected, or for developers who are writing a new storage destination provider.

**How the Storage Test Works:**

1. The tool automatically creates test files:
   * Generates files of varying sizes
   * Uses randomized file names
   * Creates the number of files you specify
2. Performs a complete backup simulation:
   * Uploads all test files to your chosen storage location
   * Downloads each file back to verify retrieval
   * Validates file integrity using hash verification
   * Repeats this cycle multiple times for confidence
3. Provides detailed test results:
   * Success/failure status of each operation
   * Upload and download performance metrics
   * Data integrity confirmation

**Customizable Test Parameters:**

* File count: Choose how many test files to generate
* File sizes: Set minimum and maximum file sizes
* Filename parameters: Configure allowed characters
* Test iterations: Specify how many test cycles to run

```
Usage: <protocol>://<username>:<password>@<path>
Example: ftp://user:pass@server/folder

Supported backends: aliyunoss,aftp,azure,b2,box,cloudfiles,dropbox,ftp,file,gcs,googledrive,e2,jottacloud,mega,msgroup,onedrivev2,openstack,rclone,s3,ssh,od4b,mssp,sharepoint,sia,storj,tahoe,cos,webdav

 --reruns (Inteiro): The number of test runs to perform
   A number that describes how many times the test is performed
   * default value:: 5
 --tempdir (Caminho): The path used to store temporary files
   The backend tester will use the system default temp path. You can set this option to choose another path.
 --extended-chars (String): A list of allowed extended filename chars
   A list of characters besides {a-z, A-Z, 0-9} to use when generating filenames
   * default value:: -_',=)(&%$#@! +
 --number-of-files (Inteiro): The number of files to test with
   An integer describing how many files to upload during a test run
   * default value:: 10
 --min-file-size (Tamanho): The minimum allowed file size
   File sizes are chosen at random, this value is the lower bound
   * default value:: 1kb
 --max-file-size (Tamanho): The maximum allowed file size
   File sizes are chosen at random, this value is the upper bound
   * default value:: 50mb
 --min-filename-length (Inteiro): The minimum allowed filename length
   File name lengths are chosen at random, this value is the lower bound
   * default value:: 5
 --max-filename-length (Inteiro): The minimum allowed filename length
   File name lengths are chosen at random, this value is the upper bound
   * default value:: 80
 --trim-filename-spaces (Boleano): Trim whitespace from filenames
   A value that indicates if whitespace should be trimmed from the ends of randomly generated filenames
   * default value:: false
 --auto-create-folder (Boleano): Allow automatic folder creation
   A value that indicates if missing folders are created automatically
   * default value:: false
 --skip-overwrite-test (Boleano): Bypass the overwrite test
   A value that indicates if dummy files should be uploaded prior to uploading the real files
   * default value:: false
 --auto-clean (Boleano): Remove any files found in target folder
   A value that indicates if all files in the target folder should be deleted before starting the first test
   * default value:: false
 --force (Boleano): Activate file deletion
   A value that indicates if existing files should really be deleted when using auto-clean
   * default value:: false
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.duplicati.com/duplicati-programs/command-line-interface-cli-1/backendtester.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.