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2bc1250c28
minor formatting and language fixes to the faq section and the appendix Signed-off-by: Dylan Whyte <d.whyte@proxmox.com>
121 lines
2.8 KiB
ReStructuredText
121 lines
2.8 KiB
ReStructuredText
File Formats
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============
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.. _pxar-format:
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Proxmox File Archive Format (``.pxar``)
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---------------------------------------
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.. graphviz:: pxar-format-overview.dot
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.. _data-blob-format:
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Data Blob Format (``.blob``)
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----------------------------
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The data blob format is used to store small binary data. The magic number
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decides the exact format:
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.. list-table::
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:widths: auto
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* - ``[66, 171, 56, 7, 190, 131, 112, 161]``
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- unencrypted
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- uncompressed
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* - ``[49, 185, 88, 66, 111, 182, 163, 127]``
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- unencrypted
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- compressed
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* - ``[123, 103, 133, 190, 34, 45, 76, 240]``
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- encrypted
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- uncompressed
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* - ``[230, 89, 27, 191, 11, 191, 216, 11]``
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- encrypted
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- compressed
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The compression algorithm used is ``zstd``. The encryption cipher is
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``AES_256_GCM``.
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Unencrypted blobs use the following format:
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.. list-table::
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:widths: auto
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* - ``MAGIC: [u8; 8]``
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* - ``CRC32: [u8; 4]``
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* - ``Data: (max 16MiB)``
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Encrypted blobs additionally contain a 16 byte initialization vector (IV),
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followed by a 16 byte authenticated encryption (AE) tag, followed by the
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encrypted data:
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.. list-table::
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* - ``MAGIC: [u8; 8]``
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* - ``CRC32: [u8; 4]``
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* - ``IV: [u8; 16]``
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* - ``TAG: [u8; 16]``
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* - ``Data: (max 16MiB)``
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.. _fixed-index-format:
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Fixed Index Format (``.fidx``)
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-------------------------------
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All numbers are stored as little-endian.
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.. list-table::
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* - ``MAGIC: [u8; 8]``
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- ``[47, 127, 65, 237, 145, 253, 15, 205]``
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* - ``uuid: [u8; 16]``,
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- Unique ID
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* - ``ctime: i64``,
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- Creation Time (epoch)
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* - ``index_csum: [u8; 32]``,
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- SHA-256 over the index (without header) ``SHA256(digest1||digest2||...)``
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* - ``size: u64``,
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- Image size
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* - ``chunk_size: u64``,
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- Chunk size
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* - ``reserved: [u8; 4016]``,
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- Overall header size is one page (4096 bytes)
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* - ``digest1: [u8; 32]``
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- First chunk digest
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* - ``digest2: [u8; 32]``
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- Second chunk digest
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* - ...
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- Next chunk digest ...
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.. _dynamic-index-format:
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Dynamic Index Format (``.didx``)
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--------------------------------
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All numbers are stored as little-endian.
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.. list-table::
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* - ``MAGIC: [u8; 8]``
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- ``[28, 145, 78, 165, 25, 186, 179, 205]``
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* - ``uuid: [u8; 16]``,
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- Unique ID
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* - ``ctime: i64``,
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- Creation Time (epoch)
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* - ``index_csum: [u8; 32]``,
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- SHA-256 over the index (without header) ``SHA256(offset1||digest1||offset2||digest2||...)``
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* - ``reserved: [u8; 4032]``,
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- Overall header size is one page (4096 bytes)
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* - ``offset1: u64``
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- End of first chunk
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* - ``digest1: [u8; 32]``
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- First chunk digest
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* - ``offset2: u64``
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- End of second chunk
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* - ``digest2: [u8; 32]``
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- Second chunk digest
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* - ...
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- Next chunk offset/digest
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