Thanks verymuch for then explanation Martin. I see your point. In fact,
we are not so worried about disaster recovery, since this files I mention in
this backup are text documents.
And generally, users ask restore of some files in particular, not
folders. Besides, they usually don't tend do delete files, they just let
them pile up in the shared folders :D
I guess using differential backup all year will not be a problem.
Thanks again Martin.
I would like if anyone else has another critic to this strategy.
Regards,
Augusto
On Nov 20, 2007 2:05 PM, Martin Simmons <[EMAIL PROTECTED]> wrote:
> >>>>> 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
> > >
>
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