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Adding a file after backups start?

Posted by George Sinclair - NOAA Federal 
George Sinclair - NOAA Federal
Adding a file after backups start?
August 10, 2018 10:59AM
If a file is added or modified after a backup starts but before any data
is sent, say while it's still walking the file system, then it's
anyone's guess whether it will get backed up on that backup, or instead
the next one, as there's no way to know how far it's into its
walk-through, i.e. whether it's already past that point.

Is that right?

So let's say the file system has a small number of inodes in use, and a
file is copied there or created just after NetWorker starts its walking,
then it would be much more likely that the file would not get backed up
this time as the walk-through might be very fast, most likely completing
before the file could be created or copied there, maybe? Alternatively,
if a very large number of inodes are in use then the probability of it
not reaching that point in its walk-through before the file is
added/copied there would be higher, albeit maybe detecting that the file
grew or changed during the save. Something like that?

I know there are a lot of factors that could come into play, but is that
the general idea?

I often see files whose ctimes (Linux) are newer than the start time of
the last incremental, but older than the completion time. These get
captured on the next incremental. I've always inferred that either they
weren't there when NetWorker walked the file system on the previous
backup, or they were, but one or more file attributes (e.g. permissions,
owner, group, etc.) was changed after the walk-through completed, or
after it passed that point where the file lived, thus being left off
that backup and not captured until the next one.

George

--
George Sinclair
Voice: (301) 713-4921
- The preceding message is personal and does not reflect any official or unofficial position of the United States Department of Commerce -
- Any opinions expressed in this message are NOT those of the US Govt. -


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