backup strategy for mirroring servers

Hi guys.
We have a DB system that is relatively small and transactions are not very
big, but very important, losing data will be very costly to the business.
I am assigned to port this system to SQL Server 2005 Sp1, we have decided to
implement the DB mirroring with the High Protection mode.
I have some questions regarding backup and restore.
Suppose we utilize 3 machines, A is the principal server, B is the mirroring
server, and C is the file server on which the backup files are stored.
My questions are:
1. Currently I have created 3 SQL Server Agent jobs to backup the principal
server, a) full backup once a day, b) differential backup once every 4 hours
,
c) transaction log back once every 15 minutes. The question is: should I
change the backup file (device) every day? Or I can use one backup
file(device) for all the backups day in and day out?
2. How do I backup the mirroring server? I think I can not do anything on
the mirroring server when it is in the Mirroring/Sync mode. And if I had the
same 3 agent jobs on the mirroring server, the jobs would fail? But what if
the principal server fails over, and mirroring server becomes the principal
server, do I have to create the backup agent jobs after failover?
3. When creating the mirroring server backup, can I reuse the same backup
file name(s) that I used on the principal server? or I better off storing th
e
backup file from the mirroring server on a different location?
4. Last question, not particular related to backup Should I store the
.MDF/.LDF file for the principal server and/or mirror server on machine C?
Thanks a lot!
WenbiaoSee comments inline below:
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://www.solidqualitylearning.com/
"Wenbiao Liang" <Wenbiao Liang@.discussions.microsoft.com> wrote in message
news:498AD6C0-1131-4DFC-9C24-3117EB7379CF@.microsoft.com...
> Hi guys.
> We have a DB system that is relatively small and transactions are not very
> big, but very important, losing data will be very costly to the business.
> I am assigned to port this system to SQL Server 2005 Sp1, we have decided
to
> implement the DB mirroring with the High Protection mode.
> I have some questions regarding backup and restore.
> Suppose we utilize 3 machines, A is the principal server, B is the mirrori
ng
> server, and C is the file server on which the backup files are stored.
> My questions are:
> 1. Currently I have created 3 SQL Server Agent jobs to backup the principa
l
> server, a) full backup once a day, b) differential backup once every 4 hou
rs,
> c) transaction log back once every 15 minutes. The question is: should I
> change the backup file (device) every day? Or I can use one backup
> file(device) for all the backups day in and day out?
You have to decide this for yourself. You most probably want a few generatio
ns of the backups, and
whether to only have those on tape and also disk will influence this. I assu
me you are aware of the
INIT and NOINIT options.

> 2. How do I backup the mirroring server? I think I can not do anything on
> the mirroring server when it is in the Mirroring/Sync mode. And if I had t
he
> same 3 agent jobs on the mirroring server, the jobs would fail? But what i
f
> the principal server fails over, and mirroring server becomes the principa
l
> server, do I have to create the backup agent jobs after failover?
Run the same job on both servers. Have a preceeding jobstep which check the
mirroring catalog view
whether that server is primary or not. If not primary, exit with success, el
se do the backup.

> 3. When creating the mirroring server backup, can I reuse the same backup
> file name(s) that I used on the principal server? or I better off storing
the
> backup file from the mirroring server on a different location?
Basically same answer as 1. Logicaly, it doesn't matter from what machine th
e backup came. This
would work in faviour for using the same backup devices.

> 4. Last question, not particular related to backup Should I store the
> .MDF/.LDF file for the principal server and/or mirror server on machine C?
No, SQL Server doesn't support storing files on a mapped/UNC drive. Need to
be local, SAN or ISCSI.

> Thanks a lot!
> Wenbiao|||Tibor is correct that you cannot store database files on a UNC share,
however, you can store the backup files on a UNC share location.
Personally, I use a script to create a new backup file on a remote share for
each backup using a date and time stamp as part of the file name (just like
a DB maintenance plan). I have a separate job to clean out old backups
which makes it easy to adjust the retention time.
Geoff N. Hiten
Senior Database Administrator
Microsoft SQL Server MVP
"Tibor Karaszi" <tibor_please.no.email_karaszi@.hotmail.nomail.com> wrote in
message news:ugBYISWwGHA.4972@.TK2MSFTNGP05.phx.gbl...
> See comments inline below:
> --
> Tibor Karaszi, SQL Server MVP
> http://www.karaszi.com/sqlserver/default.asp
> http://www.solidqualitylearning.com/
>
> "Wenbiao Liang" <Wenbiao Liang@.discussions.microsoft.com> wrote in message
> news:498AD6C0-1131-4DFC-9C24-3117EB7379CF@.microsoft.com...
> You have to decide this for yourself. You most probably want a few
> generations of the backups, and whether to only have those on tape and
> also disk will influence this. I assume you are aware of the INIT and
> NOINIT options.
>
> Run the same job on both servers. Have a preceeding jobstep which check
> the mirroring catalog view whether that server is primary or not. If not
> primary, exit with success, else do the backup.
>
> Basically same answer as 1. Logicaly, it doesn't matter from what machine
> the backup came. This would work in faviour for using the same backup
> devices.
>
> No, SQL Server doesn't support storing files on a mapped/UNC drive. Need
> to be local, SAN or ISCSI.
>
>