-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 That is the old way that pre-dates --link-dest. Instead of cp -al daily.02 daily.01 you can do a mkdir daily.01 then an rsync ... - --link-dest=../daily.02 daily.01
Rsync then doesn't need any --delete and you don't bother making any hard links that will eventually be replaced. Plus the linking happens while rsync is running so it is usually much faster. On 01/22/13 18:10, Ashley M. Kirchner wrote: > Joe, this is specific to having a backup with rsync. The way I > use links for rsync is by not using the link (ln) command at all, > but instead using cp's build-in -l (link) option. It looks > something like this: > > 1) delete the oldest backup (simple 'rm' command) 2) shift the rest > (with 'rm') by 1, so if I have a 7 day daily backup, it moves > daily.06 -> 07, daily.05 -> 06, etc., etc. This effectively > removed daily.01 as that is now .02. 3) make a linked copy of .02 > back into .01, so cp -al daily.02 daily.01 - this links only, it > doesn't physically copy anything. 4) run rsync against that .01 > backup. I run rsync with --delete and --delete-excluded options in > case something got removed from the live system, it gets deleted, > but only from this newest backup. If I need to recover it 5 days > from now, I still can by looking in daily.05. > > This setup works well in that only one folder will have actual > physical files (and thus the largest of them all.) The rest of > them are links back to it and are very small. The neat thing is, > when a file gets deleted from the newest backup, .01, it breaks the > link from the others, and the physical file remains in the next > older backup, in this case .02, (till it "expires" out of the > cycle.) > > I have 12 servers backing up gigabytes worth of data every night > like this, maintaining anywhere between 3 to 6 weeks worth for each > one. They're all going to a single 1 terabyte drive. > > A > > > > On Tue, Jan 22, 2013 at 3:31 PM, Franois <daithe...@free.fr > <mailto:daithe...@free.fr>> wrote: > > Hi Joe, > > If you want to understand hard-links, just take a look at Wikipedia > : http://en.wikipedia.org/wiki/Hard_link#Example > > I think it's pretty easy to understand. > > To understand how hard-links (and rsync) can help you make strong > incremental backups, head over > http://blog.interlinked.org/tutorials/rsync_time_machine.html > > Cheers, > > -- Franois > > > Le mardi 22 janvier 2013 23:12:38, Joe a ←crit : >> Thanks for the reply. I know what hard and soft links are and > have some >> idea of how they relate to backup. >> >> What I need is a tutorial on how all of that works with rsync. I >> can see that there are a lot of considerations as to which >> options to use for different situations and maybe some general >> strategies on how to build something like an incremental or >> differential backup. >> >> I use rsync now on a one directory tree to one directory tree > basis now, >> but I'd like to have more than one backup on my backup device >> without doubling the storage which is what hard links will help >> me do once I know how they work in more detail. >> >> Joe >> >> On 01/22/2013 02:48 AM, Tony Abernethy wrote: >>> This may help: (man ln) >>> >>> A hard link to a file is indistinguishable from the original >>> directory entry; any changes > to a >>> file are effectively independent of the name used to reference > the file. >>> Hard links may not normally refer to directories and may not > span file >>> systems. >>> >>> Assuming you do many backups and many of the files do not >>> change, hard links are your friend. >>> >>> Backing up soft links: Do you back up the link or what the link >>> points to? (Even that simple thing has interesting ways to get >>> complicated.) >>> >>> -----Original Message----- From: rsync-boun...@lists.samba.org > <mailto:rsync-boun...@lists.samba.org> >>> [mailto:rsync-boun...@lists.samba.org > <mailto:rsync-boun...@lists.samba.org>] On Behalf Of Joe Sent: > Tuesday, >>> January 22, 2013 1:32 AM To: rsync@lists.samba.org >>> <mailto:rsync@lists.samba.org> Subject: Is there a >>> howto/tutorial on backups/rsync that covers > the use >>> of hard and soft links? >>> >>> There have been a lot of posts on the list lately about issues > with hard >>> links. It has been very interesting, but I don't understand it >>> very thoroughly. I haven't used hard links for anything yet. >>> I've used symlinks - not for backups, of course - and have seen >>> them get > broken or >>> deleted in backups. >>> >>> Is there a tutorial anywhere that will explain how this works > (assuming >>> that the reader understands the basic concepts of backups and > knows how >>> to program, but doesn't really understand how to use links to >>> create things like incremental or differential backups)? It >>> seems like > there >>> are a lot of fine points to consider, some of which can really > bite you >>> if you don't take them into account. >>> >>> I'm working on my own personal backup system using bash and > rsync. When >>> it's done it will be pretty good, but it would be *much* better >>> if I rewrote it to have more backup versions using hard links >>> to save > space. >>> >>> I am writing my own because (aside from learning a lot) I have > only seen >>> two types of backup utilities - those that are very simplistic > and won't >>> let me do what I want and those which are enterprise level and >>> I > can't >>> figure out how to get them to do anything without extensive > study. (I >>> did experiment with areca (I think it uses rsync libraries >>> under the hood) which would probably do everything I want, but >>> I got stuck too many times and couldn't get enough support on >>> their forum to keep going.) >>> >>> TIA >>> >>> Joe >>> >>> -- Please use reply-all for most replies to avoid omitting the > mailing list. >>> To unsubscribe or change options: >>> https://lists.samba.org/mailman/listinfo/rsync Before posting, >>> read: http://www.catb.org/~esr/faqs/smart-questions.html > -- Please use reply-all for most replies to avoid omitting the > mailing list. To unsubscribe or change options: > https://lists.samba.org/mailman/listinfo/rsync Before posting, > read: http://www.catb.org/~esr/faqs/smart-questions.html > > > > - -- ~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~ Kevin Korb Phone: (407) 252-6853 Systems Administrator Internet: FutureQuest, Inc. ke...@futurequest.net (work) Orlando, Florida k...@sanitarium.net (personal) Web page: http://www.sanitarium.net/ PGP public key available on web site. ~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~ -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlD/HPgACgkQVKC1jlbQAQcfZgCeO25bLuBD+TdloH72nXdSJG/3 zXIAoMPt6W5ouK1V8bM7S6oenAPq7jyG =3Irt -----END PGP SIGNATURE----- -- Please use reply-all for most replies to avoid omitting the mailing list. 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