doc: add description for restore --sparse

This commit is contained in:
Michael Eischer 2023-01-10 23:09:19 +01:00
parent c354b55e62
commit b151fa498a
2 changed files with 12 additions and 1 deletions

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@ -60,6 +60,14 @@ Restoring symbolic links on windows is only possible when the user has
``SeCreateSymbolicLinkPrivilege`` privilege or is running as admin. This is a
restriction of windows not restic.
By default, restic does not restore files as sparse. Use ``restore --sparse`` to
enable the creation of sparse files if supported by the filesystem. Then restic
will restore long runs of zero bytes as holes in the corresponding files.
Reading from a hole returns the original zero bytes, but it does not consume
disk space. Note that the exact location of the holes can differ from those in
the original file, as their location is determined while restoring and is not
stored explicitly.
Restore using mount
===================

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@ -258,7 +258,10 @@ Metadata handling
~~~~~~~~~~~~~~~~~
Restic saves and restores most default attributes, including extended attributes like ACLs.
Sparse files are not handled in a special way yet, and aren't restored.
Information about holes in a sparse file is not stored explicitly, that is during a backup
the zero bytes in a hole are deduplicated and compressed like any other data backed up.
Instead, the restore command optionally creates holes in files by detecting and replacing
long runs of zeros, in filesystems that support sparse files.
The following metadata is handled by restic: