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From: Gao Xiang <>
Cc: Gao Xiang <>
Subject: [PATCH 1/2] erofs-utils: README: trivial updates
Date: Sat, 22 May 2021 13:50:56 +0800	[thread overview]
Message-ID: <> (raw)

- update erofs naming to EROFS;
- add some words about compression levels;
- add more description about legacy EROFS images.

Signed-off-by: Gao Xiang <>
 README | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/README b/README
index b57550b2a09e..bcf30e11aa52 100644
--- a/README
+++ b/README
@@ -1,7 +1,7 @@
-erofs-utils includes user-space tools for erofs filesystem.
+erofs-utils includes user-space tools for EROFS filesystem.
 Currently mkfs.erofs and erofsfuse (experimental) are available.
 Dependencies & build
@@ -50,7 +50,7 @@ as well.
-two main kinds of erofs images can be generated: (un)compressed.
+two main kinds of EROFS images can be generated: (un)compressed.
  - For uncompressed images, there will be none of compression
    files in these images. However, it can decide whether the tail
@@ -61,8 +61,8 @@ two main kinds of erofs images can be generated: (un)compressed.
    saved with compression. If not, fallback to an uncompressed
-How to generate erofs images
+How to generate EROFS images (Linux 5.3+)
 Currently lz4 and lz4hc are available for compression, e.g.
  $ mkfs.erofs -zlz4hc foo.erofs.img foo/
@@ -70,17 +70,24 @@ Currently lz4 and lz4hc are available for compression, e.g.
 Or leave all files uncompressed as an option:
  $ mkfs.erofs foo.erofs.img foo/
-How to generate legacy erofs images
+In addition, you could specify a higher compression level to get a
+(slightly) better compression ratio than the default level, e.g.
+ $ mkfs.erofs -zlz4hc,12 foo.erofs.img foo/
+How to generate legacy EROFS images (Linux 4.19+)
 Decompression inplace and compacted indexes have been introduced in
 linux-5.3, which are not forward-compatible with older kernels.
-In order to generate _legacy_ erofs images for old kernels,
+In order to generate _legacy_ EROFS images for old kernels,
 consider adding "-E legacy-compress" to the command line, e.g.
  $ mkfs.erofs -E legacy-compress -zlz4hc foo.erofs.img foo/
+For Linux kernel >= 5.3, legacy EROFS images are _NOT recommended_
+due to runtime performance loss compared with non-legacy images.
 Obsoleted erofs.mkfs
@@ -94,7 +101,7 @@ PLEASE NOTE: This version is highly _NOT recommended_ now.
 erofsfuse (experimental, unstable)
-erofsfuse is introduced to support erofs format for various platforms
+erofsfuse is introduced to support EROFS format for various platforms
 (including older linux kernels) and new on-disk features iteration.
 It can also be used as an unpacking tool for unprivileged users.
@@ -120,7 +127,7 @@ and build it manually:
 erofsfuse binary will be generated under fuse folder.
-How to mount an erofs image with erofsfuse
+How to mount an EROFS image with erofsfuse
 As the other FUSE implementations, it's quite simple to mount with
@@ -139,7 +146,7 @@ To unmount an erofsfuse mountpoint as a non-root user:
-erofs-utils is under GPLv2+ as a part of erofs project,
+erofs-utils is under GPLv2+ as a part of EROFS filesystem project,
 feel free to send patches or feedback to us.
@@ -155,7 +162,7 @@ Cc:
-[1] According to the erofs on-disk format, the tail block of files
+[1] According to the EROFS on-disk format, the tail block of files
     could be inlined aggressively with its metadata in order to reduce
     the I/O overhead and save the storage space (called tail-packing).

             reply	other threads:[~2021-05-22  5:51 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-22  5:50 Gao Xiang [this message]
2021-05-22  5:50 ` [PATCH 2/2] erofs-utils: README: big pcluster feature update Gao Xiang

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