Cloud Parallel File Storage:Limits

File system

Mounting

You can mount and access CPFS for Lingjun only from Platform for AI (PAI) (Lingjun resources, PAI general computing resources, and single-tenant PAI Lingjun resources) and Container Compute Service (ACS) (high-performance network GPU workloads). Access from ECS instances is not supported.

Operating systems

The CPFS for Lingjun client supports only Linux operating systems, such as Alibaba Cloud Linux and Ubuntu. The following table lists the supported operating system versions.

Protocol

Only the POSIX protocol is supported.

Scaling

You can only scale out CPFS for Lingjun file system instances. Scaling in is not supported. The scaling step size is 10,240 GiB, and you can scale out to 1 PiB. To create a 20 PiB file system, submit a ticket.

Data flow

• Limits on dataflows

  • CPFS for Lingjun V2.4.0 and later support dataflows within the same account. CPFS for Lingjun V2.6.0 and later support dataflows across accounts.

  • A maximum of 10 dataflows can be created for a CPFS for Lingjun file system.

  • A file path in a CPFS for Lingjun file system can be associated with only one OSS bucket.

  • You cannot create dataflows between a CPFS for Lingjun file system and an OSS bucket that resides in another region.

• Limits on path, file name and directory name

  • You cannot rename a non-empty directory in a path that is associated with a dataflow. Otherwise, the Permission Denied error message or an error message indicating that the directory is not empty is returned.

  • Proceed with caution when you use special characters in the names of directories and files.

    • The following characters are supported: letters, digits, exclamation points (!), hyphens (-), underscores (_), periods (.), asterisks (*), and parentheses (()).

    • The following characters are not supported. Otherwise, unexpected results or failures may occur:

      • Double periods (..) in subdirectory or file names.

      • Backslashes (\) or consecutive backslashes (\\) in paths.

      • Files with a forward slash (/) in their subdirectory or filename are not supported.

  • A path can be up to 1,023 characters in length.

• Limits on dataflow tasks

  • Only CPFS for Lingjun V2.6.0 and later support streaming tasks. In addition, you can use streaming tasks only by calling API operations.

  • A maximum of 4 batch tasks can be run at the same time for a dataflow. The streaming task is unlimited.

  • Limits on data import

    • After a symbolic link is imported to CPFS for Lingjun, the symbolic link is converted into a regular file that contains no symbolic link information.

    • If an OSS bucket contains data of multiple versions, only data of the latest version is imported.

    • The name of a file or a subdirectory can be up to 255 bytes in length.

  • Limits on data export

    • After a symbolic link is synchronized to OSS, the file that the symbolic link points to is not synchronized to OSS. In this case, the symbolic link is converted into a regular object that contains no data.

    • Hard links can be synchronized to OSS only as regular files that contain no link information.

    • After a file of the Socket, Device, or Pipe type is exported to an OSS bucket, the file is converted into a regular object that contains no data.

    • A directory path can be up to 1,023 characters in length.

Filesets

• Filesets

  Item	Description
  File system	Only CPFS for Lingjun V2.7.0 and later support the fileset.
  Number of filesets that can be created in a file system	500
  Number of files or directories that can be created in a fileset	10 billion
  Fileset	Nested filesets are not supported. If a fileset is specified as a parent directory, its subdirectory cannot be a fileset. Hard links cannot be created or rename operation is not supported across filesets.
  Fileset path	The path must start and end with a forward slash (/). The fileset path must be a new path and cannot be an existing path. Fileset paths cannot be modified. If the fileset path is a multi-level path, the parent directory must be an existing directory. The maximum depth supported by a fileset path is eight levels. The depth of the root directory / is 0 levels. For example, if a fileset path is /workspace/dir1/, it indicates the depth of the fileset path is two levels. The path cannot exceed 990 characters in length. The name of a single-level directory can be a maximum of 255 characters in length. The name can contain letters, digits, underscores (_), periods (.), and hyphens (-).
  Delete a fileset	Filesets can be deleted only in the NAS console or by API operation. If you delete a fileset, the fileset is moved to the recycle bin for 24 h. The storage used to store the fileset is not immediately released. If you need to immediately free up storage space, you must clear all data in the fileset, and then delete the fileset. After the data in the fileset is deleted, the data cannot be restored. Proceed with caution.

• Fileset quotas

  Limits	Description
  File system	Only CPFS for Lingjun V2.7.0 and later support setting fileset quotas.
  Quota	A fileset path supports only one quota.
  Capacity quota	The minimum capacity quota of a fileset is 10 GiB. The scaling step size is 1 GiB.
  File quota	A fileset supports a minimum of 10,000 files. The scaling step size is 1. The file quantity cannot exceed 10 billion.
  Quota write	If the size of written data reaches the capacity quota or the number of written files reaches file quota, the fileset cannot write data.
  Quota statistics	The quota statistics have a 15-minute latency. The actual usage takes effect after 15 minutes.
  Modify quota	When you modify a directory quota, you must set the quota capacity or the file quantity to be greater than the capacity or file quantity that has been used. Otherwise, an error is returned.