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Apsara File Storage NAS:Limits

Last Updated:Jan 22, 2024

This topic describes the limits of Apsara File Storage NAS (NAS) on service specifications, operating systems, protocols, networks, and features.

Limits on service specifications

Item

Description

Maximum number of file systems that can be created in each region within an Alibaba Cloud account

  • General-purpose NAS file system: 20

  • Extreme NAS file system: 200

Maximum number of mount targets for a single file system

  • General-purpose NAS file system: 2

  • Extreme NAS file system: 1

Maximum number of files in a single file system

  • General-purpose NAS file system: 1 billion

  • Extreme NAS file system: 500 million

Maximum number of directory levels in a single file system

1,000 levels

Maximum capacity of a single file system

  • Capacity NAS file system: 10 PiB

  • Performance NAS file system: 1 PiB

  • Extreme NAS file system: 256 TiB

Maximum number of compute nodes on which a file system can be mounted at the same time

1,000

Maximum size of a single file

32 TiB

Maximum number of hard links to a single file

511

Maximum number of permission groups that can be created in each region within an Alibaba Cloud account

20

Maximum number of rules that can be created for a permission group

300

Limits on throughput

The following table describes the maximum throughput of each storage type of General-purpose NAS file systems in the China (Hong Kong) region and regions outside the Chinese mainland. To increase the throughput, submit a ticket.

Storage type

Region

Zone

Maximum read throughput (GB/s)

Maximum write throughput (GB/s)

Capacity NAS file system

China (Hong Kong)

Hong Kong Zone B

10

2

Japan (Tokyo)

Tokyo Zone A

10

1

Tokyo Zone B

3

0.5

India (Mumbai)

Mumbai Zone A

10

1

Singapore

Singapore Zone A

10

1

Singapore Zone C

10

1

Australia (Sydney)

Sydney Zone A

10

1

Malaysia (Kuala Lumpur)

Kuala Lumpur Zone A

10

1

Indonesia (Jakarta)

Jakarta Zone A

10

1

Philippines (Manila)

Manila Zone A

10

1

US (Virginia)

Virginia Zone B

10

1

US (Silicon Valley)

Silicon Valley Zone B

10

1

UK (London)

London Zone A

10

1

Germany (Frankfurt)

Frankfurt Zone A

10

1

Performance NAS file system

Japan (Tokyo)

Tokyo Zone A

10

1

Tokyo Zone B

10

1

South Korea (Seoul)

Seoul Zone A

10

1

India (Mumbai)

Mumbai Zone A

10

1

Singapore

Singapore Zone A

10

2

Singapore Zone C

10

1

Australia (Sydney)

Sydney Zone A

10

1

Malaysia (Kuala Lumpur)

Kuala Lumpur Zone A

10

1

US (Virginia)

Virginia Zone A

10

1

US (Silicon Valley)

Silicon Valley Zone B

10

1

UK (London)

London Zone A

10

1

Germany (Frankfurt)

Frankfurt Zone A

20

3

Limits on operating systems

Item

Description

Image

The NAS product team has tested the kernel images and listed the recommended images for NAS. To ensure the optimal performance of NAS file systems, use the recommended kernel versions or later versions. If you do not use the recommended kernel images, NAS may become unavailable. For more information, see Recommended kernel images.

Kernel version

The NAS product team has identified some defective kernel versions and provided solutions. If you use a defective kernel version and do not upgrade the version, NAS may become unavailable. If the NAS product team identifies new issues about the adaption of kernel versions, Alibaba Cloud pushes notifications to you by using emails, internal messages, text messages, and console announcements. Make sure that the preceding communication channels are available and handle the issues at the earliest opportunity. For more information, see Known issues on NFS clients.

macOS

You can mount only Server Message Block (SMB) file systems on macOS.

AIX

Not supported.

Limits on protocols

Network File System (NFS) file systems

Item

Description

Naming conventions

The name of a file cannot exceed 255 bytes in length.

Protocol versions

Only NFSv3 and NFSv4.0 are supported.

File features

The POSIX SetUID, SetGID, and sticky bit features are not supported.

NFSv4.0 attributes

The following attributes are not supported:

  • FATTR4_MIMETYPE

  • ATTR4_QUOTA_AVAIL_HARD

  • FATTR4_QUOTA_AVAIL_SOFT

  • FATTR4_QUOTA_USED

  • FATTR4_TIME_BACKUP

  • FATTR4_TIME_CREATE

  • FATTR4_ARCHIVE

If you use an unsupported attribute, an NFS4ERR_ATTRNOTSUPP error code is logged in the /var/log/messages file.

NFSv4.0 operations

The following operations are not supported:

  • OP_DELEGPURGE

  • OP_DELEGRETURN

  • NFS4_OP_OPENATTR

If you call an unsupported operation, an NFS4ERR_ATTRNOTSUPP error code is logged in the /var/log/messages file.

NFSv4.0 features

The delegation feature is not supported.

UIDs and GIDs

  • On Linux, the mappings between user IDs (UIDs) and usernames and the mappings between group IDs (GIDs) and group names are defined in configuration files. For NFSv3 file systems, if the mapping between an ID and a name is defined in a configuration file, the name is used to represent the user or group. If no mapping is defined for an ID, the ID is used.

  • For NFSv4.0 file systems, if the version of the Linux kernel is earlier than 3.0, the usernames and group names of all files are identified as nobody. If the version of the Linux kernel is 3.0 or later, the rule that is used by NFSv3 file systems applies.

    Note

    If the Linux kernel version is earlier than 3.0, we recommend that you do not run the chown or chgrp command for files or directories in an NFSv4.0 file system. Otherwise, the UID and GID of the file or directory are changed to nobody.

NFS clients

  • For General-purpose NAS file systems, an NFS client can send a maximum of 128 concurrent requests.

  • For General-purpose NAS file systems, the maximum bandwidth of an NFS client is 500 MB/s.

  • You can open a maximum of 32,768 files at a time on an NFS client. The files in the list folder and its subfolders are not counted.

  • Each mount on an NFS client can obtain up to 8,192 locks across a maximum of 256 file-process pairs. For example, a single process can obtain one or more locks on 256 separate files, or 8 processes can each obtain one or more locks on 32 files.

  • We recommend that you do not use an NFS client on an Elastic Compute Service (ECS) instance to access an NFS file system.

File and directory types

Extreme NAS file systems support the following types of files and directories: REG, DIR, SYMLINK, and LINK.

SMB file systems

Item

Description

Naming conventions

The name of a file cannot exceed 255 UTF-16 characters in length.

Features

  • SMB file systems do not support extended file attributes or lease-based client-side caching.

  • SMB file systems do not support I/O control (IOCTL) or file system control (FSCTL) operations. For example, you cannot create sparse files, compress files, check the status of network interface cards (NICs), or create reparse points.

  • SMB file systems do not support alternate data streams.

  • SMB file systems do not support identity authentication based on Lightweight Directory Access Protocol (LDAP).

  • SMB file systems do not support the following features: SMB Direct, SMB Multichannel, SMB Directory Leasing, and persistent file handles.

Protocol versions

SMB 2.1 and later are supported.

SMB clients

Each file or directory can be opened by up to 8,192 users at a time. This limit applies across all compute nodes on which the file system is mounted and all users that share access to the file system. This indicates that each file or directory can have up to 8,192 active file handles. A file system can have a maximum of 65,536 active file handles.

Limits on networks

Item

Description

Classic network

  • You cannot mount a NAS file system on an ECS instance that belongs to another Alibaba Cloud account.

  • If the IP address of a mount target is changed due to kernel limits, the NAS file system may become inaccessible.

    In this case, Alibaba Cloud pushes notifications to you by using emails, internal messages, text messages, intelligent voice reminders, and console announcements 30 days in advance. Remount the file system within 30 days after you receive the notifications.

Network of General-purpose NAS file systems

General-purpose NAS file systems use the new-generation high-performance network transmission channel of Alibaba Cloud. This channel does not support custom TCP options. If you use custom TCP options, the NAS file system may fail to be mounted.

Limits on lifecycle policies

Item

Description

File system type

Only General-purpose NAS file systems support lifecycle policies.

Number of lifecycle policies

You can create a maximum of 20 lifecycle policies in each region within an Alibaba Cloud account.

Limits on directory quotas

Item

Description

File system type

Only General-purpose NFS file systems support quota management.

Quota

For a single file system, you can configure quotas for a maximum of 500 directories. The maximum directory depth is eight levels. For example, the depth of the root directory / is zero level. The depth of the /workspace directory is one level. The depth of the /workspace/dir1 directory is two levels.