On 02/11/2015 11:13 AM, Les Mikesell wrote:
On Wed, Feb 11, 2015 at 11:02 AM, Francis Gerund <ranrund@xxxxxxxxx> wrote:
Hello.
After some reading, including the rsync man page, I am still not clear on
this:
When using rsync to backup and restore, when should and when should one
*not*
include hard links (by using the -H option switch)?
A simple example case would be backups for one or just a few light-duty
local workstations. Is there a simple, clear rule about that, or is it too
complicated for that?
Use it unless the resulting backup run is too slow to be practical -
which will only be when there are vast numbers of hardlinks in the
filesystem which is pretty rare (backuppc's archive, for example).
That is, if you don't know whether or not you need it you are better
off retaining as much of the original filesystem attributes as
possible in your backups. But, keep in mind that it can only
reproduce the hardlinks that exist in the portion of the filesystem
that is covered in one run. If you do multiple runs covering
different subdirectories, it can't duplicate hardlinks outside of each
run.
/var/lib/yum/yumdb and, to a lesser extent, /usr/share/zoneinfo are
two places that use hard links a lot. If you _don't_ use "-H" you
make multiple, independent copies of each file and have no way to
restore the original hard link structure. If all you care about is
not losing data, then it's just a space issue. If the ability to
restore the original hard link relationships is important, then
using "-H" is a must, no matter the performance penalty.
--
Bob Nichols "NOSPAM" is really part of my email address.
Do NOT delete it.
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