2018-06-18 20:17:30 +00:00
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***********
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Local Cache
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***********
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In order to speed up certain operations, restic manages a local cache of data.
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This document describes the data structures for the local cache with version 1.
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Versions
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========
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The cache directory is selected according to the `XDG base dir specification
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<http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html>`__.
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2018-10-11 12:00:51 +00:00
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Each repository has its own cache sub-directory, consisting of the repository ID
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2018-06-18 20:17:30 +00:00
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which is chosen at ``init``. All cache directories for different repos are
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independent of each other.
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The cache dir for a repo contains a file named ``version``, which contains a
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single ASCII integer line that stands for the current version of the cache. If
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a lower version number is found the cache is recreated with the current
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version. If a higher version number is found the cache is ignored and left as
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is.
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Snapshots, Data and Indexes
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===========================
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Snapshot, Data and Index files are cached in the sub-directories ``snapshots``,
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``data`` and ``index``, as read from the repository.
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Expiry
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======
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Whenever a cache directory for a repo is used, that directory's modification
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timestamp is updated to the current time. By looking at the modification
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timestamps of the repo cache directories it is easy to decide which directories
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are old and haven't been used in a long time. Those are probably stale and can
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be removed.
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