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 Log backup failure

Author  Topic 

ravilobo
Master Smack Fu Yak Hacker

1184 Posts

Posted - 2008-06-12 : 15:22:58
My backup plan is as follows (SQL2K5)
Weekly full
Daily diff
Hourly log


Hourly log fails daily at particular time with following error -
BACKUP LOG cannot be performed because there is no current database backup.

It works , once I kick off a FULL backup.

I feel there is some activity which disqualifies the log sequence. Any thoughts?


------------------------
I think, therefore I am - Rene Descartes

tkizer
Almighty SQL Goddess

38200 Posts

Posted - 2008-06-12 : 15:55:46
This occurs when no full backup has ever been taken on a database, so if you create a new database and did not perform a full backup before the diff or tlog backup kicks off, then you will get an error. I am rewriting my isp_Backup stored procedure (see my blog) to handle this condition.

I don't understand what you mean by "some activity which disqualifies the log sequence". Please explain in better detail.

Tara Kizer
Microsoft MVP for Windows Server System - SQL Server
http://weblogs.sqlteam.com/tarad/

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ravilobo
Master Smack Fu Yak Hacker

1184 Posts

Posted - 2008-06-12 : 16:14:49
This is NOT a case of log backup happening before the FULL backup. Although the error message says so. That mostly in the case of new DBs.

I do have a FULL backup.

I believe this is the backup architecture,
1. FULL backup acts as a starting pint
2. first LOG backup contains the activities after the full backup
3. second LOG backups is from the point where first has stopped and so on….

Somewhere in this sequence, because of some activity this chain is breaking. I am trying to figure that thing. Hope this is clear.


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tkizer
Almighty SQL Goddess

38200 Posts

Posted - 2008-06-12 : 16:20:42
Did someone truncate the transaction log?

Tara Kizer
Microsoft MVP for Windows Server System - SQL Server
http://weblogs.sqlteam.com/tarad/

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ravilobo
Master Smack Fu Yak Hacker

1184 Posts

Posted - 2008-06-12 : 16:27:04
No. No one has access to the server. Does DB shrink truncates the log? I am sure it won't, still...

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I think, therefore I am - Rene Descartes
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tkizer
Almighty SQL Goddess

38200 Posts

Posted - 2008-06-12 : 16:38:51
The shrink does not impact the transaction log according to BOL.

I know I saw an email from a fellow DBA here that encountered this issue when a full backup does exist. I'm pretty sure he researched it and found it to be a bug. I'll see if I can dig it up.

Tara Kizer
Microsoft MVP for Windows Server System - SQL Server
http://weblogs.sqlteam.com/tarad/

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ravilobo
Master Smack Fu Yak Hacker

1184 Posts

Posted - 2008-06-12 : 16:42:44
Thank you Tara.

Interestingly this is happening exactly at the same time everyday! So I am going to put a trace and check.

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I think, therefore I am - Rene Descartes
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tkizer
Almighty SQL Goddess

38200 Posts

Posted - 2008-06-12 : 16:46:52
I found the email. He said he located a hotfix for it and is ordering it from MS. He also found a work-around for it, which can be found in here: http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1293496&SiteID=1

Tara Kizer
Microsoft MVP for Windows Server System - SQL Server
http://weblogs.sqlteam.com/tarad/

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ravilobo
Master Smack Fu Yak Hacker

1184 Posts

Posted - 2008-06-12 : 17:03:11
Thank you Tara!

After reading the links, it looks like if I stop the VSS SQL writer service, things should work fine.

I will update my findings….


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I think, therefore I am - Rene Descartes
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shafi.spl
Starting Member

10 Posts

Posted - 2008-06-14 : 04:38:54
i think there is some modifications occurs in the data base.
so ,we have to take the full backup before log backup


i think , therefore i am - shafi
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tkizer
Almighty SQL Goddess

38200 Posts

Posted - 2008-06-14 : 15:18:57
quote:
Originally posted by shafi.spl

i think there is some modifications occurs in the data base.
so ,we have to take the full backup before log backup


i think , therefore i am - shafi



That isn't true.

Tara Kizer
Microsoft MVP for Windows Server System - SQL Server
http://weblogs.sqlteam.com/tarad/

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ravilobo
Master Smack Fu Yak Hacker

1184 Posts

Posted - 2008-06-16 : 10:33:27
Agree with Tara. In my case though - there was a third party tool taking backup and truncating the log; finally figured it out. Thanks Tara.

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