Problems with rsync 2.5.1pre1 and hardlinks

[birger at takatukaland.de]

Dave Dykstra schrieb am Mon, Dec 10, 2001 at 02:21:46PM -0600:
[...]
* > 
* > * 
* > * Ideas:
* > *     1. Would it be possible to use symlinks instead of hardlinks?  That
* > * 	would give you more flexibility to split things up however you
* > * 	like.
* > *     2. Perhaps you could break it up into ~70 copies, where each time you
* > * 	give it the first directory that contains the data and another
* > * 	one that contains one of the hardlinks.
* > 
* > Both alternatives will eat up huge amounts of disk space as the numbers
* > above suggest.  I will therefore consider plugging in more mem/swap before
* > trying them.
* 
* Why would symlinks eat up disk space?

Correction, of course they don't.  I have to use hardlinks because every
directory provides a chrooted environment that'll break when using symlinks.


* 
* I only suggested the second alternative because I thought that it would
* end up with all the destination files hardlinked together as on the
* original system.  I hadn't tested it, but now I did and it works:
* 
*     $ mkdir s s/d1 s/d2 s/d3 t
*     $ touch s/d1/l1
*     $ ln s/d1/l1 s/d2/l1
*     $ ln s/d1/l1 s/d3/l1
*     $ ls -li s/*/l1
* 	286226 -rw-rw-r--   3 dwd      dwd            0 Dec 10 14:20 s/d1/l1
* 	286226 -rw-rw-r--   3 dwd      dwd            0 Dec 10 14:20 s/d2/l1
* 	286226 -rw-rw-r--   3 dwd      dwd            0 Dec 10 14:20 s/d3/l1
*     $ rsync -aH s/d1 s/d2 t
*     $ rsync -aH s/d1 s/d3 t
*     $ ls -li t/*/l1
* 	622728 -rw-rw-r--   3 dwd      dwd            0 Dec 10 14:20 t/d1/l1
* 	622728 -rw-rw-r--   3 dwd      dwd            0 Dec 10 14:20 t/d2/l1
* 	622728 -rw-rw-r--   3 dwd      dwd            0 Dec 10 14:20 t/d3/l1

Ah, now I understand what you mean.  Yes that will surely work and minimize
memory utilisation on the cost of a somewhat complex rsync mechanism.  I'll
definitely fall back on that technique if I'll be still short on memory after
some upgrades.

("somewhat complex": the backup server does not know anything about the 
 directories to be synced, maybe there will be new ones - so you'll have
 to provide a comprehensive list of the dirs from the main server to set
 up the logic above)


- Birger