Compress

In CloudMount

Needs Pro. See Wrapping and combining drives.

At a glance

rclone support tier: Tier 4: Experimental

This is a wrapping drive: it stores nothing itself and works on top of other drives, so checksums, modification times, server-side operations and free space mostly follow the drives it wraps. The sections below say where it differs.

Warning

This remote is currently experimental. Things may break and data may be lost. Anything you do with this remote is at your own risk. Please understand the risks associated with using experimental code and don’t use this remote in critical applications.

The Compress remote adds compression to another remote. It is best used with remotes containing many large compressible files.

Setup notes

In CloudMount you add this drive from the Add drive screen, and the wizard asks for the options listed under Options. The notes below come from rclone’s setup guide.

Compression Algorithms

GZIP – a well-established and widely adopted algorithm that strikes a solid balance between compression speed and ratio. It supports compression levels from -2 to 9, with the default -1 (roughly equivalent to level 5) offering an effective middle ground for most scenarios.
Zstandard (zstd) – a modern, high-performance algorithm that offers precise control over the trade-off between speed and compression efficiency. Compression levels range from 0 (no compression) to 4 (maximum compression).

File types

If you open a remote wrapped by compress, you will see that there are many files with an extension corresponding to the compression algorithm you chose. These files are standard files that can be opened by various archive programs, but they have some hidden metadata that allows them to be used by rclone. While you may download and decompress these files at will, do not manually delete or rename files. Files without correct metadata files will not be recognized by rclone.

File names

The compressed files will be named *.###########.gz where * is the base file and the # part is base64 encoded size of the uncompressed file. The file names should not be changed by anything other than the rclone compression backend.

Options

Standard options

The wizard asks for these when you add the drive.

remote

Remote to compress.

Type: string · Required

mode

Compression mode.

Type: string · Default: gzip

Choices:

gzip: Standard gzip compression with fastest parameters.
zstd: Zstandard compression — fast modern algorithm offering adjustable speed-to-compression tradeoffs.

level

GZIP (levels -2 to 9):

-2 — Huffman encoding only. Only use if you know what you’re doing.
-1 (default) — recommended; equivalent to level 5.
0 — turns off compression.
1–9 — increase compression at the cost of speed. Going past 6 generally offers very little return.

ZSTD (levels 0 to 4):

0 — turns off compression entirely.
1 — fastest compression with the lowest ratio.
2 (default) — good balance of speed and compression.
3 — better compression, but uses about 2–3x more CPU than the default.
4 — best possible compression ratio (highest CPU cost).

Notes:

Choose GZIP for wide compatibility; ZSTD for better speed/ratio tradeoffs.
Negative gzip levels: -2 = Huffman-only, -1 = default (≈ level 5).

Type: string · Required

Advanced options

The wizard shows these under Advanced options. Most drives work without changing any of them.

ram_cache_limit

Some remotes don’t allow the upload of files with unknown size. In this case the compressed file will need to be cached to determine it’s size.

Files smaller than this limit will be cached in RAM, files larger than this limit will be cached on disk.

Type: SizeSuffix · Default: 20Mi

description

Description of the remote.

Type: string