TLog management in DB Mirroring

11 Jun 2009 8:38 AM

Abba

Hello,

Iam doing an analysis of DB Mirroring for our new SQL2008 servers. My
understanding is that there would not be any transfer of Tlogs from
Principal to Mirrored server. The individual T-Log records are transferred
using TCP endpoints. That way I do not have to worry about purging/deleting
TLog backups in the Mirrored server.

Please let me know if Iam wrong here..

TIA,
AbbA

11 Jun 2009 9:07 AM

Tibor Karaszi

That is correct.

--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://sqlblog.com/blogs/tibor_karaszi

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"Abba" <SQL_H***@aaa.com> wrote in message news:uTC2QAn6JHA.6004@TK2MSFTNGP02.phx.gbl...
> Hello,
>
> Iam doing an analysis of DB Mirroring for our new SQL2008 servers. My understanding is that there
> would not be any transfer of Tlogs from Principal to Mirrored server. The individual T-Log records
> are transferred using TCP endpoints. That way I do not have to worry about purging/deleting TLog
> backups in the Mirrored server.
>
> Please let me know if Iam wrong here..
>
> TIA,
> AbbA
>

11 Jun 2009 12:15 PM

Abba

Thanks Tibor. I got confused when it was mentioned as 'network' in:
http://ts2blogs.com/blogs/bva/archive/2008/05/16/sql-server-2008-database-mirroring.aspx#180123

"in the past, database mirroring occasionally had performance issues related
to moving transaction log data from the principal to the mirrored databases.
In response, SQL Server 2008 now reduces the amount of information that is
moved across the network from the principal's transaction log to the
mirror's transaction log by compressing the information before sending it to
the mirror's transaction log for hardening."

Now, I guess the author meant the transfer from one Endpoint to another.

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"Tibor Karaszi" <tibor_please.no.email_kara***@hotmail.nomail.com> wrote in
message news:uI$iAQn6JHA.3860@TK2MSFTNGP05.phx.gbl...
> That is correct.
>
> --
> Tibor Karaszi, SQL Server MVP
> http://www.karaszi.com/sqlserver/default.asp
> http://sqlblog.com/blogs/tibor_karaszi
>
>
> "Abba" <SQL_H***@aaa.com> wrote in message
> news:uTC2QAn6JHA.6004@TK2MSFTNGP02.phx.gbl...
>> Hello,
>>
>> Iam doing an analysis of DB Mirroring for our new SQL2008 servers. My
>> understanding is that there would not be any transfer of Tlogs from
>> Principal to Mirrored server. The individual T-Log records are
>> transferred using TCP endpoints. That way I do not have to worry about
>> purging/deleting TLog backups in the Mirrored server.
>>
>> Please let me know if Iam wrong here..
>>
>> TIA,
>> AbbA
>>
>
>

11 Jun 2009 5:35 PM

Tibor Karaszi

> Now, I guess the author meant the transfer from one Endpoint to
> another.

Yep.

--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://sqlblog.com/blogs/tibor_karaszi

Show quoteHide quote

"Abba" <SQL_H***@aaa.com> wrote in message
news:OJBWh5o6JHA.2656@TK2MSFTNGP05.phx.gbl...
> Thanks Tibor. I got confused when it was mentioned as 'network' in:
> http://ts2blogs.com/blogs/bva/archive/2008/05/16/sql-server-2008-database-mirroring.aspx#180123
>
> "in the past, database mirroring occasionally had performance issues
> related to moving transaction log data from the principal to the
> mirrored databases. In response, SQL Server 2008 now reduces the
> amount of information that is moved across the network from the
> principal's transaction log to the mirror's transaction log by
> compressing the information before sending it to the mirror's
> transaction log for hardening."
>
> Now, I guess the author meant the transfer from one Endpoint to
> another.
>
> "Tibor Karaszi" <tibor_please.no.email_kara***@hotmail.nomail.com>
> wrote in message news:uI$iAQn6JHA.3860@TK2MSFTNGP05.phx.gbl...
>> That is correct.
>>
>> --
>> Tibor Karaszi, SQL Server MVP
>> http://www.karaszi.com/sqlserver/default.asp
>> http://sqlblog.com/blogs/tibor_karaszi
>>
>>
>> "Abba" <SQL_H***@aaa.com> wrote in message
>> news:uTC2QAn6JHA.6004@TK2MSFTNGP02.phx.gbl...
>>> Hello,
>>>
>>> Iam doing an analysis of DB Mirroring for our new SQL2008 servers.
>>> My understanding is that there would not be any transfer of Tlogs
>>> from Principal to Mirrored server. The individual T-Log records
>>> are transferred using TCP endpoints. That way I do not have to
>>> worry about purging/deleting TLog backups in the Mirrored server.
>>>
>>> Please let me know if Iam wrong here..
>>>
>>> TIA,
>>> AbbA
>>>
>>
>>
>
>

12 Jun 2009 4:19 AM

news.microsoft.com

Yes or no.

Correct, you don't need to worry about log backups on the mirror. However,
if you are maintaining a database mirroring set that supports automatic
failover, your mirror may become your principle, and your log backup setup
may need to survive the failover.

Linchi

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"Abba" <SQL_H***@aaa.com> wrote in message
news:uTC2QAn6JHA.6004@TK2MSFTNGP02.phx.gbl...
> Hello,
>
> Iam doing an analysis of DB Mirroring for our new SQL2008 servers. My
> understanding is that there would not be any transfer of Tlogs from
> Principal to Mirrored server. The individual T-Log records are transferred
> using TCP endpoints. That way I do not have to worry about
> purging/deleting TLog backups in the Mirrored server.
>
> Please let me know if Iam wrong here..
>
> TIA,
> AbbA
>

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