@@ -22,42 +22,44 @@ separate page: :ref:`disaster-recovery-experts`.
2222Data pool damage (files affected by lost data PGs)
2323--------------------------------------------------
2424
25- If a PG is lost in a *data * pool, then the file system will continue
26- to operate normally, but some parts of some files will simply
27- be missing (reads will return zeros).
25+ If a PG is lost in a *data * pool, then the file system continues to operate
26+ normally, but some parts of some files will simply be missing (reads will
27+ return zeros).
2828
29- Losing a data PG may affect many files. Files are split into many objects,
30- so identifying which files are affected by loss of particular PGs requires
31- a full scan over all object IDs that may exist within the size of a file.
32- This type of scan may be useful for identifying which files require
33- restoring from a backup.
29+ Losing a data PG may affect many files. Files are split into many objects, so
30+ identifying which files have been affected by the loss of particular PGs
31+ requires a full scan over all object IDs that may exist within the size of a
32+ file. This type of scan may be useful for identifying which files must be
33+ restored from a backup.
3434
3535.. danger ::
3636
3737 This command does not repair any metadata, so when restoring files in
38- this case you must *remove * the damaged file, and replace it in order
39- to have a fresh inode. Do not overwrite damaged files in place.
38+ this case you must *remove * the damaged file and replace it in order
39+ to have a fresh inode. Do not overwrite damaged files in place.
4040
4141If you know that objects have been lost from PGs, use the ``pg_files ``
42- subcommand to scan for files that may have been damaged as a result:
42+ subcommand to scan for the files that may have been damaged as a result:
4343
4444::
4545
4646 cephfs-data-scan pg_files <path> <pg id> [<pg id>...]
4747
48- For example, if you have lost data from PGs 1.4 and 4.5, and you would like
49- to know which files under /home/bob might have been damaged:
48+ For example, if you have lost data from PGs 1.4 and 4.5 and you want to know
49+ which files under `` /home/bob `` have been damaged:
5050
5151::
5252
5353 cephfs-data-scan pg_files /home/bob 1.4 4.5
5454
55- The output will be a list of paths to potentially damaged files, one
55+ The output is a list of paths to potentially damaged files. One file is listed
5656per line.
5757
58- Note that this command acts as a normal CephFS client to find all the
59- files in the file system and read their layouts, so the MDS must be
60- up and running.
58+ .. note ::
59+
60+ This command acts as a normal CephFS client to find all the files in the
61+ file system and read their layouts. This means that the MDS must be up and
62+ running in order for this command to be usable.
6163
6264Using first-damage.py
6365---------------------
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