Could making an extra backup cause data loss?

I'm wondering whether in some circumstances, making an additional SQL backup
could cause data loss.
For ezample, a database is configured with the full recovery model. The DBA,
Alice, has scheduled daily full backups at 0200, and transaction log backups
at 0000, 0600, 1200 and 1800.
Suppose programmer Bob makes an additional full backup at 1000 so that he
can copy the database to his laptop, then removes this backup from the
server and doesn't tell Alice.
What happens if Alice wants to do a restore at 1201? Can she just restore
the 0200 full backup followed by the 0600 and 1200 transaction log backups,
or will there be missing data between 0600 and 1000?
Any comments appreciated. Thanks,
SimonHi
A full back does not affect the transaction log sequence as long as you do
not set it to truncate the log also (option when you do it through
Enterprise Manager).
In your case, the full backup contains all the data and the log from 0600,
but does not truncate the log. The 1200 log dump contains the log from 0600
to 1200.
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/
"Simon" <simon@.antispam.aardvarks> wrote in message
news:419524d5$0$226$bed64819@.news.gradwell.net...
> I'm wondering whether in some circumstances, making an additional SQL
backup
> could cause data loss.
> For ezample, a database is configured with the full recovery model. The
DBA,
> Alice, has scheduled daily full backups at 0200, and transaction log
backups
> at 0000, 0600, 1200 and 1800.
> Suppose programmer Bob makes an additional full backup at 1000 so that he
> can copy the database to his laptop, then removes this backup from the
> server and doesn't tell Alice.
> What happens if Alice wants to do a restore at 1201? Can she just restore
> the 0200 full backup followed by the 0600 and 1200 transaction log
backups,
> or will there be missing data between 0600 and 1000?
> Any comments appreciated. Thanks,
> Simon
>|||As mike says - the good thing about log backups is that they are not affected
by full backups - if you have the sequence of logs you can restore from any
full backup.
It's important that Bob doesn't do a log backup though as this will cause
problems - even if he uses the NO_TRUNCATE option.
"Simon" wrote:
> I'm wondering whether in some circumstances, making an additional SQL backup
> could cause data loss.
> For ezample, a database is configured with the full recovery model. The DBA,
> Alice, has scheduled daily full backups at 0200, and transaction log backups
> at 0000, 0600, 1200 and 1800.
> Suppose programmer Bob makes an additional full backup at 1000 so that he
> can copy the database to his laptop, then removes this backup from the
> server and doesn't tell Alice.
> What happens if Alice wants to do a restore at 1201? Can she just restore
> the 0200 full backup followed by the 0600 and 1200 transaction log backups,
> or will there be missing data between 0600 and 1000?
> Any comments appreciated. Thanks,
> Simon
>
>