# erofs - man(5) - [phpMan]

[_erofs_(5)](https://www.chedong.com/phpMan.php/man/erofs/5/markdown)                                 File Formats Manual                                [_erofs_(5)](https://www.chedong.com/phpMan.php/man/erofs/5/markdown)

## NAME
       erofs - the Enhanced Read-Only File System

## DESCRIPTION
       **erofs  **is a create-once read-only filesystem, with support for compression and a multi-device
       backing store.

       There are two inode formats:

       •  32-byte compact with 16-bit UID/GID, 32-bit file size, and no file times
       •  64-byte extended with 32-bit UID/GID, 64-bit file size, and a modification time (_st_mtim_).

### Mount options
### user_xattr
### nouser_xattr
              Controls whether _user_ extended attributes are exposed.  Defaults to yes.

### acl
       **noacl  **Controls whether POSIX [**acl**(5)](https://www.chedong.com/phpMan.php/man/acl/5/markdown)s are exposed.  Defaults to yes.

       **cache_strategy**=**disabled**|**readahead**|**readaround**
              Cache allocation for compressed files: never, if reading from start of  file,  regard‐
              less of position.  Defaults to **readaround**.

### dax
       **dax**=**always**|**never**
              Direct  Access  control.   If  **always **and the source device supports DAX, uncompressed
              non-inlined files will be read directly, without going through the page cache.  **dax **is
              a synonym for **always**.  Defaults to unset, which is equivalent to **never**.

       **device**=_blobdev_
              Add extra device holding some of the data.  Must be given as many  times  and  in  the
              same order as **--blobdev **was to [**mkfs.erofs**(1)](https://www.chedong.com/phpMan.php/man/mkfs.erofs/1/markdown).

       **domain_id**=_did_
       **fsid**=_id_
              Control CacheFiles on-demand read support.  To be documented.

## VERSIONS
       **erofs  **images are versioned through the use of feature flags; these are listed in the **-E **sec‐
       tion of [**mkfs.erofs**(1)](https://www.chedong.com/phpMan.php/man/mkfs.erofs/1/markdown),

## CONFIGURATION
       Linux must be configured with the **CONFIG_EROFS_FS **option to mount EROFS  filesystems.   There
       are sub-configuration items that restrict the availability of some of the parameters above.

## SEE ALSO
       [**mkfs.erofs**(1)](https://www.chedong.com/phpMan.php/man/mkfs.erofs/1/markdown), [**fsck.erofs**(1)](https://www.chedong.com/phpMan.php/man/fsck.erofs/1/markdown), [**dump.erofs**(1)](https://www.chedong.com/phpMan.php/man/dump.erofs/1/markdown)

       _Documentation/filesystems/erofs.txt_ in the Linux source.

Linux man-pages 6.7                          2023-10-31                                     [_erofs_(5)](https://www.chedong.com/phpMan.php/man/erofs/5/markdown)