Blobfuse2 Limitations Issues

BlobFuse2 doesn't guarantee 100% POSIX compliance because BlobFuse2 simply translates requests into Blob REST APIs. For example, rename operations are atomic in POSIX but not in BlobFuse2.

Differences between the Linux file system and BlobFuse2

In many ways, you can use BlobFuse2-mounted storage just like the native Linux file system. The virtual directory scheme is the same and uses a forward slash (/) as a delimiter. Basic file system operations like mkdir, opendir, readdir, rmdir, open, read, create, write, close, unlink, truncate, stat, and rename work the same as in the Linux file system.

BlobFuse2 is different from the Linux file system in some key ways:

• Readdir count of hard links:

For performance reasons, BlobFuse2 doesn't correctly report the hard links inside a directory. The number of hard links for empty directories returns as 2. The number for non-empty directories always returns as 3, regardless of the actual number of hard links.

• Non-atomic renames:

Azure Blob Storage doesn't support atomic rename operations. Single-file renames are actually two operations: a copy, and then a deletion of the original. Directory renames recursively enumerate all files in the directory and renames each file.

• Special files:

BlobFuse2 supports only directories, regular files, and symbolic links. Special files like device files, pipes, and sockets aren't supported.

• mkfifo:

Fifo creation isn't supported by BlobFuse2. Attempting this action results in a "function not implemented" error.

• chown and chmod:

BlobFuse2 does not support chown operations for either block blob storage (FNS) or Data Lake Storage (HNS). FNS storage accounts do not support chmod operations, HNS storage accounts do support chmod operations but only on child objects inside of the mount directory, not on the root mount directory.

• Device files or pipes:

BlobFuse2 doesn't support creating device files or pipes.

• Extended-attributes (x-attrs):

BlobFuse2 doesn't support extended-attributes (x-attrs) operations.

• Write-streaming:

Concurrent streaming of read and write operations on large file data might produce unpredictable results. Simultaneously writing to the same blob from different threads isn't supported.