rsync - using a --files-from list to cut out scanning. How to handle deletions? (fwd)
paul+rsync at wurtel.net
Fri Jan 18 02:54:06 MST 2013
On Fri 18 Jan 2013, Robert Bell wrote:
> >If a file exists in the target directory when using --link-dest rsync
> >modifies the link rather than replacing it which means you don't have
> >history for files that have been replaced rather than added or deleted.
> Thanks for your astute observation about updating hard-linked
> files: you had me worried for a while.
> Fortunately, we are using the --whole-file option in our production
> backups, since the target of our backups is an HSM system (SGI's DMF),
> and we don't want rsync to start comparing files (and thus triggering a
> recall). With this option, if a file is changed between the source and
> a target which contains a hard-linked version of the file, then the
> rsync update replaces the file in the target, not overwrites it and all
> its hard-linked cousins. Whew!
Rsync will not update an existing file in-place unless you use the
--inplace option. So --whole-file is irrelevant for this.
Rsync (without --inplace) will always create a new (temporary) file,
using the existing data (without --whole-file) to enable the delta diff
speedup algorithm. Once the temp file is successfully created, it's
renamed to the original name, deleting the existing link. So any
hardlinked data will remain untouched.
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