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nix/doc/manual/src/command-ref/nix-store/optimise.md
John Ericson 043135a848 Document file system object content addressing
In addition:

- Take the opportunity to add a bunch more missing hyperlinks, too.

- Remove some glossary entries that are now subsumed by dedicated pages.
  We used to not be able to do this without breaking link fragments, but
  now we can, so pick up where we left off.

Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
2024-05-15 16:28:48 -04:00

1.2 KiB

Name

nix-store --optimise - reduce disk space usage

Synopsis

nix-store --optimise

Description

The operation --optimise reduces Nix store disk space usage by finding identical files in the store and hard-linking them to each other. It typically reduces the size of the store by something like 25-35%. Only regular files and symlinks are hard-linked in this manner. Files are considered identical when they have the same Nix Archive (NAR) serialisation: that is, regular files must have the same contents and permission (executable or non-executable), and symlinks must have the same contents.

After completion, or when the command is interrupted, a report on the achieved savings is printed on standard error.

Use -vv or -vvv to get some progress indication.

{{#include ./opt-common.md}}

{{#include ../opt-common.md}}

{{#include ../env-common.md}}

Example

$ nix-store --optimise
hashing files in `/nix/store/qhqx7l2f1kmwihc9bnxs7rc159hsxnf3-gcc-4.1.1'
...
541838819 bytes (516.74 MiB) freed by hard-linking 54143 files;
there are 114486 files with equal contents out of 215894 files in total