Backup and availability

Technically what exactly does the backup do ?, and what can users/sysadmins
do in a database when a backup is in progress ?
Does it put table/page locks on data when it is backing up that specific
table/page or does it back up the actual mdf/ndf file ?.
How does this change with Full, differencial, filegroup and transaction
backups ?
When backing up a database I have read that it is not possible to run some
ALTER DATABASE commands, inserts and deletes etc, but i have also read that
backups maximize their rate of data transfer with minimal effect on
transaction throughput.
I am starting suspect that you are able to use DML statements and not DDLs
during a backup.
As long as Ive been a DBA i have always done Backups at times when there are
the least amount of users and when the server is not being utilised so much,
this make perfect sense as I'm sure theres an overhead.
Ive looked on the web and in BOL but cant find anything specific.
any knowledge or help on this would be appreciated
thanksHi!
You will find a lot of info at
http://www.microsoft.com/technet/pr...chap/4297b.asp.
Dejan Sarka, SQL Server MVP
Associate Mentor
www.SolidQualityLearning.com
"piripi" <piripi@.discussions.microsoft.com> wrote in message
news:EA51C857-126E-4835-AF3F-C46DA996C439@.microsoft.com...
> Technically what exactly does the backup do ?, and what can
> users/sysadmins
> do in a database when a backup is in progress ?
> Does it put table/page locks on data when it is backing up that specific
> table/page or does it back up the actual mdf/ndf file ?.
> How does this change with Full, differencial, filegroup and transaction
> backups ?
> When backing up a database I have read that it is not possible to run some
> ALTER DATABASE commands, inserts and deletes etc, but i have also read
> that
> backups maximize their rate of data transfer with minimal effect on
> transaction throughput.
> I am starting suspect that you are able to use DML statements and not DDLs
> during a backup.
> As long as Ive been a DBA i have always done Backups at times when there
> are
> the least amount of users and when the server is not being utilised so
> much,
> this make perfect sense as I'm sure theres an overhead.
> Ive looked on the web and in BOL but cant find anything specific.
> any knowledge or help on this would be appreciated
> thanks