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152 lines
3.9 KiB
ReStructuredText
152 lines
3.9 KiB
ReStructuredText
:orphan:
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==============================================
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ceph-dencoder -- ceph encoder/decoder utility
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==============================================
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.. program:: ceph-dencoder
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Synopsis
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========
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| **ceph-dencoder** [commands...]
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Description
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===========
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**ceph-dencoder** is a utility to encode, decode, and dump ceph data
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structures. It is used for debugging and for testing inter-version
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compatibility.
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**ceph-dencoder** takes a simple list of commands and performs them
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in order.
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Commands
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========
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.. option:: version
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Print the version string for the **ceph-dencoder** binary.
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.. option:: import <file>
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Read a binary blob of encoded data from the given file. It will be
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placed in an in-memory buffer.
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.. option:: export <file>
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Write the contents of the current in-memory buffer to the given
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file.
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.. option:: list_types
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List the data types known to this build of **ceph-dencoder**.
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.. option:: type <name>
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Select the given type for future ``encode`` or ``decode`` operations.
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.. option:: skip <bytes>
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Seek <bytes> into the imported file before reading data structure, use
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this with objects that have a preamble/header before the object of interest.
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.. option:: decode
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Decode the contents of the in-memory buffer into an instance of the
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previously selected type. If there is an error, report it.
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.. option:: encode
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Encode the contents of the in-memory instance of the previously
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selected type to the in-memory buffer.
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.. option:: dump_json
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Print a JSON-formatted description of the in-memory object.
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.. option:: count_tests
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Print the number of built-in test instances of the previosly
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selected type that **ceph-dencoder** is able to generate.
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.. option:: select_test <n>
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Select the given build-in test instance as a the in-memory instance
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of the type.
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.. option:: get_features
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Print the decimal value of the feature set supported by this version
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of **ceph-dencoder**. Each bit represents a feature. These correspond to
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CEPH_FEATURE_* defines in src/include/ceph_features.h.
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.. option:: set_features <f>
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Set the feature bits provided to ``encode`` to *f*. This allows
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you to encode objects such that they can be understood by old
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versions of the software (for those types that support it).
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Example
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=======
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Say you want to examine an attribute on an object stored by ``ceph-osd``. You can do this:
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::
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$ cd /mnt/osd.12/current/2.b_head
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$ attr -l foo_bar_head_EFE6384B
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Attribute "ceph.snapset" has a 31 byte value for foo_bar_head_EFE6384B
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Attribute "ceph._" has a 195 byte value for foo_bar_head_EFE6384B
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$ attr foo_bar_head_EFE6384B -g ceph._ -q > /tmp/a
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$ ceph-dencoder type object_info_t import /tmp/a decode dump_json
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{ "oid": { "oid": "foo",
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"key": "bar",
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"snapid": -2,
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"hash": 4024842315,
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"max": 0},
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"locator": { "pool": 2,
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"preferred": -1,
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"key": "bar"},
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"category": "",
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"version": "9'1",
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"prior_version": "0'0",
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"last_reqid": "client.4116.0:1",
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"size": 1681,
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"mtime": "2012-02-21 08:58:23.666639",
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"lost": 0,
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"wrlock_by": "unknown.0.0:0",
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"snaps": [],
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"truncate_seq": 0,
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"truncate_size": 0,
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"watchers": {}}
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Alternatively, perhaps you wish to dump an internal CephFS metadata object, you might
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do that like this:
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::
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$ rados -p metadata get mds_snaptable mds_snaptable.bin
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$ ceph-dencoder type SnapServer skip 8 import mds_snaptable.bin decode dump_json
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{ "snapserver": { "last_snap": 1,
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"pending_noop": [],
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"snaps": [],
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"need_to_purge": {},
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"pending_create": [],
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"pending_destroy": []}}
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Availability
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============
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**ceph-dencoder** is part of Ceph, a massively scalable, open-source, distributed storage system. Please
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refer to the Ceph documentation at http://ceph.com/docs for more
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information.
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See also
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========
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:doc:`ceph <ceph>`\(8)
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