mirror of https://github.com/dswd/zvault
66 lines
2.2 KiB
Markdown
66 lines
2.2 KiB
Markdown
zvault-vacuum(1) -- Reclaim space by rewriting bundles
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======================================================
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## SYNOPSIS
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`zvault vacuum [OPTIONS] <REPO>`
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## DESCRIPTION
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This subcommand reclaims space by rewriting bundles in the repository `REPO`.
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This command rewrites bundles to remove unused chunks of backups that have been
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removed by _zvault-remove(1)_ or _zvault-prune(1)_.
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To accomplish this, it will scan all backups and track all used chunks to
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identify chunks that are not used by any backup. Those chunks are then grouped
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by bundle and bundles with many unused chunks will be rewritten with those
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chunks left out.
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The option `--ratio` configures the minimal ratio of used chunks in a bundle
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required to remove it. Since all chunks that are still used must be read from
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the bundle and written to a new one and only the storage space of the unused
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chunks can be reclaimed, rewriting a bundle is more economical the lower the
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ratio. At a ratio of 0% will only rewrite bundles with no used chunks at all
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(in this case the bundle is just removed). At a ratio of 100%, all bundles will
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be rewritten regardless of unused chunks.
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Please note that the bundles will be rewritten with the current settings for
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encryption and compression, disregarding the original settings during bundle
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creation.
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Unless `--force` is set, this command will only simulate the process but not
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actually rewrite any bundle.
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As this is a critical operation, zVault takes many precaution measures to avoid
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any damaging the integrity to the repository or other backups. The whole process
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is performed with an exclusive lock on the repository which prevents any backup
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runs. Also the chunk index is double checked before removing bundles to make
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sure that they are unused. Nevertheless, this is a critical operation which
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should be avoided when the storage space permits it.
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## OPTIONS
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* `-r`, `--ratio <NUM>`:
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Do not rewrite bundles with more than `NUM`% of used chunks.
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The ratio must be given in whole percentage, e.g. 50 mean 50%.
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* `-f`, `--force`:
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Actually run the vacuum instead of simulating it.
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* `-h`, `--help`:
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Prints help information
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## COPYRIGHT
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Copyright (C) 2017 Dennis Schwerdel
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This software is licensed under GPL-3 or newer (see LICENSE.md)
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