How long will a differential backup take?

How can I determine how long a differential backup will take to complete? I
think reading the "differential change map" pages of the database would help,
but I don't know how to do that or even if it is possible.
Tanks,
Bruce.
bpettus wrote:
> How can I determine how long a differential backup will take to
> complete? I think reading the "differential change map" pages of the
> database would help, but I don't know how to do that or even if it is
> possible.
> Tanks,
> Bruce.
Since the operation depends on the amount of data to be backed up, the
utilization on the server, the speed of the disk array, and the backup
software you are using, it's really impossible to tell. What I suggest
you do is perform some tests on the system in question and monitor disk
and CPU activity at the same time using perfmon to better give you the
estimates you need. I would also consider you look into a third-party
backup/recovery solution that implements compression to shorten the
backup period. Quest sells LiteSpeed for SQL Server. There are solutions
from other vendors as well.
David Gugick
Quest Software
www.quest.com
|||Maybe my question wasn't clear enough. I'm looking to find the percentage of
data that would be contained in a differential backup. I could compare that
with the duration of a full backup to fudge a duration estimate. For
example, given a database of 100GB and a differential backup that would
contain 50GB, I could then say "the differential backup would take about 50%
the time of the full backup". I'm not looking for anything precise but
rather an educated guess.
I could do some tests and obtain a benchmark but I'm in a time crunch and
testing is not an option at this point.
Thanks,
Bruce.
"David Gugick" wrote:

> bpettus wrote:
> Since the operation depends on the amount of data to be backed up, the
> utilization on the server, the speed of the disk array, and the backup
> software you are using, it's really impossible to tell. What I suggest
> you do is perform some tests on the system in question and monitor disk
> and CPU activity at the same time using perfmon to better give you the
> estimates you need. I would also consider you look into a third-party
> backup/recovery solution that implements compression to shorten the
> backup period. Quest sells LiteSpeed for SQL Server. There are solutions
> from other vendors as well.
> --
> David Gugick
> Quest Software
> www.quest.com
>
|||Hi
Yes, roughly, 100/50GB gives you 50% of the time.
Regards
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mike@.epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"bpettus" <bpettus@.discussions.microsoft.com> wrote in message
news:D08FAB04-F368-4C48-9084-20DBB219273C@.microsoft.com...[vbcol=seagreen]
> Maybe my question wasn't clear enough. I'm looking to find the percentage
> of
> data that would be contained in a differential backup. I could compare
> that
> with the duration of a full backup to fudge a duration estimate. For
> example, given a database of 100GB and a differential backup that would
> contain 50GB, I could then say "the differential backup would take about
> 50%
> the time of the full backup". I'm not looking for anything precise but
> rather an educated guess.
> I could do some tests and obtain a benchmark but I'm in a time crunch and
> testing is not an option at this point.
> Thanks,
> Bruce.
> "David Gugick" wrote: