>>>>> On Tue, 20 Nov 2007 13:14:24 -0300, Augusto Camarotti said: > > Hi Mark, thanks for the reply > > When I was saying the generally 3 GB of data was added, I was counting on > data changed, since new data is being added when a change is made. I just > don`t express it right.
Ah, OK. > I didnt understand why it'll be a problem not tracking deleted files, since > the reason of a backup is to save data that have been added, and not > deleted. It depends on the purpose of your backup, e.g. is it to allow for restores of corrupted/lost files or is it for disaster recovery? Some people don't like Differentials for disaster recovery. Suppose the Full backup contains file A and B. Someone decides that file A is junk so they delete it and they create file C instead. The next Differential backup will contain file C and nothing else. This looks OK because all files are saved in some backup. However, when your disk gets trashed and you have to do a restore from the Full and Differential backups. The problem is that you will get back all three files A, B and C. __Martin > > Waiting for new sugestions or critics, > > Augusto > > On Nov 20, 2007 8:09 AM, Martin Simmons <[EMAIL PROTECTED]> wrote: > > > >>>>> On Mon, 19 Nov 2007 18:55:30 -0300, Augusto Camarotti said: > > > > > > Nowadays we have a backup strategy like this : > > > Daily Backup = Monday-Thursday = Full Backups with individual tapes for > > each > > > weekday. > > > Weekly Backup = 2nd-5th Friday =3D Full Backups with individual tapes > > for 7 > > > Fridays > > > Montly Backup = 1st Friday = Full Backups with individual tapes for 12 > > > months > > > > > > This way I'm using 23 tapes. > > > > > > Then I was reading about Differential backups, and this strategy came > > into > > > my mid : > > > > > > - One Full Backup on the first day of the year, say 2nd January (since > > 1st > > > it's a holyday) on disk, in the storage machine. The data would be > > stored in > > > a tape, which would be taken offsite. > > > - 364 Differential backups, one for each day of the year. Using the 23 > > tapes > > > to do it. > > > > > > Since the amount of data added on a year it's a maximum of 3 GB, the 23 > > > tapes will be enough to backup every day on a year. > > > > Beware that the amount of new data added in a year is not sufficient to > > calculate this. You also need to include the amount of data *changed* > > since > > the beginning of the year, because that will be backed up each day. > > > > > > > Well, as I didn't find any recomendations to this strategy, I was in > > doubt > > > if it would be fine to do this way. > > > > > > Suggestions or Critics are welcome. > > > > Differential/incremental backups have a disadvantage that they do not > > track > > deleted files, which could be a major problem over a whole year. > > > > __Martin > > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
