forked from mirrors/nixpkgs
37 lines
1.3 KiB
XML
37 lines
1.3 KiB
XML
<section xmlns="http://docbook.org/ns/docbook"
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xmlns:xlink="http://www.w3.org/1999/xlink"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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version="5.0"
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xml:id="sec-nix-store-corruption">
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<title>Nix Store Corruption</title>
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<para>
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After a system crash, it’s possible for files in the Nix store to become
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corrupted. (For instance, the Ext4 file system has the tendency to replace
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un-synced files with zero bytes.) NixOS tries hard to prevent this from
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happening: it performs a <command>sync</command> before switching to a new
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configuration, and Nix’s database is fully transactional. If corruption
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still occurs, you may be able to fix it automatically.
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</para>
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<para>
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If the corruption is in a path in the closure of the NixOS system
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configuration, you can fix it by doing
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<screen>
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# nixos-rebuild switch --repair
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</screen>
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This will cause Nix to check every path in the closure, and if its
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cryptographic hash differs from the hash recorded in Nix’s database, the
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path is rebuilt or redownloaded.
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</para>
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<para>
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You can also scan the entire Nix store for corrupt paths:
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<screen>
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# nix-store --verify --check-contents --repair
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</screen>
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Any corrupt paths will be redownloaded if they’re available in a binary
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cache; otherwise, they cannot be repaired.
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</para>
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</section>
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