POSIX Explained

What is POSIX?

The Portable Operating System Interface (🌐 POSIX) is a set of IEEE specifications intended to encourage compatibility between disparate Linux/UNIX flavors through standardized definitions of APIs, shells, interfaces, commands, etc.

Writing an application (or binary) which meets POSIX standards means that the program is “portable,” and is more likely to run correctly no matter what UNIX-based OS it is installed on.

Some applications may (or may not) require strict POSIX-compliance to work properly.

Object Mount’s POSIX Mode

To support those programs and applications that require POSIX-compliant interfaces, access-control, and metadata, Object Mount includes POSIX Mode.

When activated, POSIX Mode enables the necessary additional features to support applications that rely on the rigid, traditional UNIX-style file permissions and metadata.

Object storage, by default, lacks concepts like file ownership, permissions, and modification timestamps that are normal features of most local drives and file system calls. Object Mount’s POSIX Mode recreates these features and behaviors in the object storage world.

When enabled, POSIX Mode generates, stores, and maintains the metadata that is typically expected in a local file system, including:

• File ownership (uid, gid)
• Read/Write/Execute permissions
• Timestamps (mtime, ctime, etc.)
• Symbolic links and directory flags (where supported)

To retain this metadata, Object Mount creates and writes to a hidden index file that is stored at the root of your object storage bucket.

When to Enable Object Mount’s POSIX Mode

You should enable POSIX mode in Object Mount if:

• You are working with software that checks for or enforces POSIX-style permissions
• You require symbolic link emulation or fine-grained permission mapping
• You are mounting object storage as a shared filesystem in team environments

Enabling POSIX mode is recommended for workflows such as:

• Media Production
• Backup Solutions
• Archive Systems
• File Synchronization
• File Manager/Tools

When NOT to Enable Object Mount’s POSIX Mode

You should not enable POSIX Mode in Object Mount for:

• Read-only Bucket Credentials

  POSIX Mode requires write access to the object storage bucket in order to create and write to the hidden metadata file. If your credentials are read-only, POSIX mode will not function and may prevent the mount from working correctly.

• Lightweight Access

  For read-only workflows or general content browsing, POSIX mode is typically unnecessary and can be left disabled.

Enabling POSIX Mode: macOS and Windows

POSIX mode is enabled on a mount-by-mount basis: You can choose which mounts require it and which don’t.

You enable POSIX mode when creating a new mount within Object Mount for macOS or Windows.

Enabling POSIX mode in macOS and Windows environments is done through Object Mount’s graphical user interface (GUI).

See the associated page for your operating system:

• Enabling POSIX Mode when creating a mount in macOS
• Enabling POSIX Mode creating a mount in Windows

Enabling POSIX Mode: Linux

POSIX support in Object Mount for Linux includes more options, more modes, and offers more controls for the end user to configure their environment according to their unique needs and use cases.

Configuration of POSIX options in Object Mount for Linux is achieved:

• Via the command line interface (the Object Mount CLI)
• Through the setting of environment variables
• Applying “tags” directly to cloud buckets using your object storage provider’s dashboard

Use the links below to learn about the many POSIX Modes, options, and settings — and then enable the correct POSIX Mode for you use case: