EROFS

EROFS
Developer(s)	Huawei
Full name	Enhanced Read-Only File System
Introduced	November 24, 2019 with Linux 5.4
Limits
Max file size	4 GiB (version 1); 16 EiB (version 2);
Max no. of files	65,536 (version 1); 4,294,967,296 (version 2);
Max filename length	255 bytes
Features
Dates recorded	Create (version 2 only)
Date resolution	1 ns
Attributes	POSIX, xattr
File system; permissions	POSIX, ACL
Transparent; compression	Yes (LZ4)
Other
Supported; operating systems	Linux

EROFS (Enhanced Read-Only File System) is a read-only file system for Linux developed by Gao Xiang (Chinese: 高翔) of Huawei.

EROFS is a lightweight file system, it aims to improve performance and compress storage capacity.^[2] This file system is developed on the premise that it is used on smartphones like Android.^[3]^[4]

The file system was merged into the mainline kernel with Linux kernel v5.4.^[5]

All of Huawei's new products shipped with EMUI 9.0.1 or later used EROFS,^[6] and it was promoted as one of the key features of EMUI 9.1.^[2]

Features

The file system has two different inode versions. One is limited (version 1), and the other is extended (version 2).^[1]

The random read speed is 20% faster than ext4^[2]
2 GiB more storage space than other file systems^[2]
Little-endian on-disk design^[1]
Metadata and data could be mixed by design^[1]
Support POSIX attributes and permissions, xattr and ACL^[1]
Transparent compression with LZ4^[1]

References

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Gao Xiang. "erofs.txt". git.kernel.org. Retrieved 2019-09-03.
^ ^a ^b ^c ^d "EMUI 9.1, the Intelligent Android OS". HUAWEI Global. Huawei Technologies. Retrieved 2019-09-03.
^ Michael Larabel (2018-11-19). "There Is Finally A User-Space Utility To Make EROFS Linux File-Systems". Phoronix. Phoronix. Retrieved 2018-12-13.
^ Xiang, Gao (2018-05-31). "erofs: introduce erofs file system". Linux kernel (Mailing list). Retrieved 2018-12-13. {{cite mailing list}}: Unknown parameter |mailinglist= ignored (|mailing-list= suggested) (help)
^ corbet (2019-11-25). "The 5.4 kernel has been released". LWN.net. Retrieved 2019-12-01.
^ Xiang, Gao (2019-07-04). "erofs: promote erofs from staging". Linux kernel (Mailing list). Retrieved 2019-09-03. {{cite mailing list}}: Unknown parameter |mailinglist= ignored (|mailing-list= suggested) (help)

External links

Gao Xiang's Linux kernel repo - git.kernel.org
erofs-utils - git.kernel.org
EROFS, an Introduction and our Smartphone Practice on YouTube

[erofs_documentation-1] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Gao Xiang. "erofs.txt". git.kernel.org. Retrieved 2019-09-03.

[emui_9.1-2] "EMUI 9.1, the Intelligent Android OS". HUAWEI Global. Huawei Technologies. Retrieved 2019-09-03.

[3] Michael Larabel (2018-11-19). "There Is Finally A User-Space Utility To Make EROFS Linux File-Systems". Phoronix. Phoronix. Retrieved 2018-12-13.

[4] Xiang, Gao (2018-05-31). "erofs: introduce erofs file system". Linux kernel (Mailing list). Retrieved 2018-12-13. {{cite mailing list}}: Unknown parameter |mailinglist= ignored (|mailing-list= suggested) (help)

[5] rbet (2019-11-25). "The 5.4 kernel has been released". LWN.net. Retrieved 2019-12-01.

[6] Xiang, Gao (2019-07-04). "erofs: promote erofs from staging". Linux kernel (Mailing list). Retrieved 2019-09-03. {{cite mailing list}}: Unknown parameter |mailinglist= ignored (|mailing-list= suggested) (help)

[1]

[2]

[3]

[4]

[5]

[6]

Features

See also

References

External links