https://github.com/kilobyte/compsize

btrfs: find compression type/ratio on a file or set of files
https://github.com/kilobyte/compsize

Last synced: about 2 months ago
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btrfs: find compression type/ratio on a file or set of files

• Host: GitHub
• URL: https://github.com/kilobyte/compsize
• Owner: kilobyte
• License: other
• Created: 2017-09-04T14:33:33.000Z (almost 7 years ago)
• Default Branch: master
• Last Pushed: 2023-12-25T11:30:56.000Z (6 months ago)
• Last Synced: 2024-01-27T10:35:48.597Z (5 months ago)
• Language: C
• Size: 120 KB
• Stars: 318
• Watchers: 18
• Forks: 19
• Open Issues: 14
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Lists

• cli-apps - compsize - Find compression type/ratio on a file or set of files on a btrfs file system. (<a name="file-handling"></a>File and file system handling)
• awesome-cli-apps - compsize - Find compression type/ratio on a file or set of files on a btrfs file system. (<a name="file-handling"></a>File and file system handling)

README

        
# compsize

compsize takes a list of files (given as arguments) on a btrfs filesystem

and measures used compression types and effective compression ratio,

producing a report such as:

```

[~]$ compsize /home

Processed 140058 files, 133128 regular extents (196786 refs), 80886 inline.

Type       Perc     Disk Usage   Uncompressed Referenced

TOTAL       93%       14G          15G          12G

none       100%       13G          13G          10G

zlib        41%      628M         1.4G         1.4G

zstd        28%       42M         148M         148M

```

A directory has no extents but has a (recursive) list of files.  A

non-regular file is silently ignored.

As it makes no sense to talk about compression ratio of a partial extent,

every referenced extent is counted whole, exactly once -- no matter if you

use only a few bytes of a 1GB extent or reflink it a thousand times.  Thus,

the uncompressed size will not match the number given by **tar** or **du**.

On the other hand, the space _used_ should be accurate (although obviously

it can be shared with files outside our set).

The fields are:

 * Type: compression algorithm used

 * Perc: disk usage/uncompressed -- ie, effective compression ratio

 * Disk Usage: blocks actually used on the disk

 * Uncompressed: extents before compression

 * Referenced: apparent size of files (minus holes)

The ioctl used requires root.

# Installation:

Besides regular C toolchain, you need btrfs userspace headers.  On Debian

(incl. derivatives like Ubuntu) they're in libbtrfs-dev, SuSE ships them

inside libbtrfs-devel, they used to come with btrfs-progs before.

Required kernel: 3.16, btrfs-progs: 3.18 (untested!).