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author | 2018-01-04 13:43:33 +0800 | |
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committer | 2018-01-05 11:59:39 +0800 | |
commit | 812ff6ca9fcd3e629e49d4328905f33eee8ca3f5 (patch) | |
tree | 04ece7b4da00d9d2f98093774594f4057ae561d4 /src/ceph/doc/cephfs/cephfs-journal-tool.rst | |
parent | 15280273faafb77777eab341909a3f495cf248d9 (diff) |
initial code repo
This patch creates initial code repo.
For ceph, luminous stable release will be used for base code,
and next changes and optimization for ceph will be added to it.
For opensds, currently any changes can be upstreamed into original
opensds repo (https://github.com/opensds/opensds), and so stor4nfv
will directly clone opensds code to deploy stor4nfv environment.
And the scripts for deployment based on ceph and opensds will be
put into 'ci' directory.
Change-Id: I46a32218884c75dda2936337604ff03c554648e4
Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>
Diffstat (limited to 'src/ceph/doc/cephfs/cephfs-journal-tool.rst')
-rw-r--r-- | src/ceph/doc/cephfs/cephfs-journal-tool.rst | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/src/ceph/doc/cephfs/cephfs-journal-tool.rst b/src/ceph/doc/cephfs/cephfs-journal-tool.rst new file mode 100644 index 0000000..0dd54fb --- /dev/null +++ b/src/ceph/doc/cephfs/cephfs-journal-tool.rst @@ -0,0 +1,238 @@ + +cephfs-journal-tool +=================== + +Purpose +------- + +If a CephFS journal has become damaged, expert intervention may be required +to restore the filesystem to a working state. + +The ``cephfs-journal-tool`` utility provides functionality to aid experts in +examining, modifying, and extracting data from journals. + +.. warning:: + + This tool is **dangerous** because it directly modifies internal + data structures of the filesystem. Make backups, be careful, and + seek expert advice. If you are unsure, do not run this tool. + +Syntax +------ + +:: + + cephfs-journal-tool journal <inspect|import|export|reset> + cephfs-journal-tool header <get|set> + cephfs-journal-tool event <get|splice|apply> [filter] <list|json|summary> + + +The tool operates in three modes: ``journal``, ``header`` and ``event``, +meaning the whole journal, the header, and the events within the journal +respectively. + +Journal mode +------------ + +This should be your starting point to assess the state of a journal. + +* ``inspect`` reports on the health of the journal. This will identify any + missing objects or corruption in the stored journal. Note that this does + not identify inconsistencies in the events themselves, just that events are + present and can be decoded. + +* ``import`` and ``export`` read and write binary dumps of the journal + in a sparse file format. Pass the filename as the last argument. The + export operation may not work reliably for journals which are damaged (missing + objects). + +* ``reset`` truncates a journal, discarding any information within it. + + +Example: journal inspect +~~~~~~~~~~~~~~~~~~~~~~~~ + +:: + + # cephfs-journal-tool journal inspect + Overall journal integrity: DAMAGED + Objects missing: + 0x1 + Corrupt regions: + 0x400000-ffffffffffffffff + +Example: Journal import/export +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +:: + + # cephfs-journal-tool journal export myjournal.bin + journal is 4194304~80643 + read 80643 bytes at offset 4194304 + wrote 80643 bytes at offset 4194304 to myjournal.bin + NOTE: this is a _sparse_ file; you can + $ tar cSzf myjournal.bin.tgz myjournal.bin + to efficiently compress it while preserving sparseness. + + # cephfs-journal-tool journal import myjournal.bin + undump myjournal.bin + start 4194304 len 80643 + writing header 200.00000000 + writing 4194304~80643 + done. + +.. note:: + + It is wise to use the ``journal export <backup file>`` command to make a journal backup + before any further manipulation. + +Header mode +----------- + +* ``get`` outputs the current content of the journal header + +* ``set`` modifies an attribute of the header. Allowed attributes are + ``trimmed_pos``, ``expire_pos`` and ``write_pos``. + +Example: header get/set +~~~~~~~~~~~~~~~~~~~~~~~ + +:: + + # cephfs-journal-tool header get + { "magic": "ceph fs volume v011", + "write_pos": 4274947, + "expire_pos": 4194304, + "trimmed_pos": 4194303, + "layout": { "stripe_unit": 4194304, + "stripe_count": 4194304, + "object_size": 4194304, + "cas_hash": 4194304, + "object_stripe_unit": 4194304, + "pg_pool": 4194304}} + + # cephfs-journal-tool header set trimmed_pos 4194303 + Updating trimmed_pos 0x400000 -> 0x3fffff + Successfully updated header. + + +Event mode +---------- + +Event mode allows detailed examination and manipulation of the contents of the journal. Event +mode can operate on all events in the journal, or filters may be applied. + +The arguments following ``cephfs-journal-tool event`` consist of an action, optional filter +parameters, and an output mode: + +:: + + cephfs-journal-tool event <action> [filter] <output> + +Actions: + +* ``get`` read the events from the log +* ``splice`` erase events or regions in the journal +* ``apply`` extract filesystem metadata from events and attempt to apply it to the metadata store. + +Filtering: + +* ``--range <int begin>..[int end]`` only include events within the range begin (inclusive) to end (exclusive) +* ``--path <path substring>`` only include events referring to metadata containing the specified string +* ``--inode <int>`` only include events referring to metadata containing the specified string +* ``--type <type string>`` only include events of this type +* ``--frag <ino>[.frag id]`` only include events referring to this directory fragment +* ``--dname <string>`` only include events referring to this named dentry within a directory + fragment (may only be used in conjunction with ``--frag`` +* ``--client <int>`` only include events from this client session ID + +Filters may be combined on an AND basis (i.e. only the intersection of events from each filter). + +Output modes: + +* ``binary``: write each event as a binary file, within a folder whose name is controlled by ``--path`` +* ``json``: write all events to a single file, as a JSON serialized list of objects +* ``summary``: write a human readable summary of the events read to standard out +* ``list``: write a human readable terse listing of the type of each event, and + which file paths the event affects. + + +Example: event mode +~~~~~~~~~~~~~~~~~~~ + +:: + + # cephfs-journal-tool event get json --path output.json + Wrote output to JSON file 'output.json' + + # cephfs-journal-tool event get summary + Events by type: + NOOP: 2 + OPEN: 2 + SESSION: 2 + SUBTREEMAP: 1 + UPDATE: 43 + + # cephfs-journal-tool event get list + 0x400000 SUBTREEMAP: () + 0x400308 SESSION: () + 0x4003de UPDATE: (setattr) + / + 0x40068b UPDATE: (mkdir) + diralpha + 0x400d1b UPDATE: (mkdir) + diralpha/filealpha1 + 0x401666 UPDATE: (unlink_local) + stray0/10000000001 + diralpha/filealpha1 + 0x40228d UPDATE: (unlink_local) + diralpha + stray0/10000000000 + 0x402bf9 UPDATE: (scatter_writebehind) + stray0 + 0x403150 UPDATE: (mkdir) + dirbravo + 0x4037e0 UPDATE: (openc) + dirbravo/.filebravo1.swp + 0x404032 UPDATE: (openc) + dirbravo/.filebravo1.swpx + + # cephfs-journal-tool event get --path /filebravo1 list + 0x40785a UPDATE: (openc) + dirbravo/filebravo1 + 0x4103ee UPDATE: (cap update) + dirbravo/filebravo1 + + # cephfs-journal-tool event splice --range 0x40f754..0x410bf1 summary + Events by type: + OPEN: 1 + UPDATE: 2 + + # cephfs-journal-tool event apply --range 0x410bf1.. summary + Events by type: + NOOP: 1 + SESSION: 1 + UPDATE: 9 + + # cephfs-journal-tool event get --inode=1099511627776 list + 0x40068b UPDATE: (mkdir) + diralpha + 0x400d1b UPDATE: (mkdir) + diralpha/filealpha1 + 0x401666 UPDATE: (unlink_local) + stray0/10000000001 + diralpha/filealpha1 + 0x40228d UPDATE: (unlink_local) + diralpha + stray0/10000000000 + + # cephfs-journal-tool event get --frag=1099511627776 --dname=filealpha1 list + 0x400d1b UPDATE: (mkdir) + diralpha/filealpha1 + 0x401666 UPDATE: (unlink_local) + stray0/10000000001 + diralpha/filealpha1 + + # cephfs-journal-tool event get binary --path bin_events + Wrote output to binary files in directory 'bin_events' + |