Ossfs 2.0 overview

Scenarios

ossfs 2.0 supports new compute-intensive workloads such as AI training, inference, and autonomous driving. These workloads typically involve sequential and random reading, sequential (append-only) writing, without requiring complete POSIX semantics.

Operating environment

ossfs 2.0 is developed based on FUSE (Filesystem in Userspace). It currently supports x86_64 architecture and Alibaba Cloud Linux systems with kernel versions 3.10 or later.

Limits

• Permission requirements: Ensure that the AccessKey has full permissions for the target bucket or prefix-related resources. Otherwise, mounting might fail or functions might not work properly.

• Storage class limitations: Does not support mounting buckets with Archive Storage, Cold Archive, or Deep Cold Archive storage classes.

• Filename limitations: Maximum filename length is 255 characters (following Linux restrictions). Files or directories in OSS that exceed this limit will not be visible in the mount point.

• File reading limitations: Newly written files will only be uploaded to OSS after the file is closed. Reading a file that is still being written and not yet closed might cause errors.

• File writing limitations: Random writes and concurrent writes to the same file are not supported. By default, writes create non-appendable OSS objects. The default part size for writing is 8388608 bytes (8 MiB), which means the maximum supported file size for writing is 83886080000 bytes (78.125 GiB). The part size can be configured using the mount option upload_buffer_size.

• File rename operations (non-atomic)

  • Files: First copied and then the remote file is deleted.

  • Directories: All files are copied first, then the source files are deleted in batch. Directory renaming has a default limit of 2 million descendant files. This limit can be configured using the mount option rename_dir_limit.

• Concurrent write consistency: Data consistency cannot be guaranteed when multiple clients mount the same bucket and write to the same file simultaneously.

• POSIX API compatibility: Partially compatible. For details, see POSIX API support.

Function introduction

Further references

• Install ossfs 2.0.

• Configure ossfs 2.0.

• ossfs 2.0 mount options.

• Mount a bucket to a local system using ossfs 2.0.

• FAQ.

• Release notes.