Large difference between backup size and db size

Large difference between backup size and db size

Post by Marcus Coope » Fri, 30 Mar 2001 09:23:20



Hello,

I have a database who's backup is 1.8GB, but the database is 4.7GB (470MB
free) and small log (<1MB)

Why is there such a big difference?

Marcus

 
 
 

Large difference between backup size and db size

Post by Umachandar Jayachandra » Fri, 30 Mar 2001 12:27:08



probably there are deallocated pages that are still being seen as used. This
will account for the free size display. The BACKUP on the other hand will
contain only the allocated pages.
    There are also bugs related to text page deallocation that have been
corrected in later SQL70 service packs. So are you on the latest service
pack too?

--
Umachandar Jayachandran
SQL Resources at http://www.umachandar.com/resources.htm
( Please reply only to newsgroup. )

 
 
 

Large difference between backup size and db size

Post by Chri » Fri, 30 Mar 2001 13:10:57


Hi

I dont quite have this problem, but btw, are you sure that the backup file
containing one and only one backup?  surely there is no other backup sets in
the file?

My problem is differential backups, a full backup took  800Mb, the next
differential took 400Mb and the next one after that tookl 700Mb???? this is
on a DB that changes about 2mb of data a day!!

Cheers

Chris


Quote:> Hello,

> I have a database who's backup is 1.8GB, but the database is 4.7GB (470MB
> free) and small log (<1MB)

> Why is there such a big difference?

> Marcus

 
 
 

Large difference between backup size and db size

Post by Marcus Coope » Sat, 31 Mar 2001 01:13:32


Thanks,

It looks like all that is unallocated is the 10% of the database that I
specified the last time I ran a dbcc shrinkdatabase.   Before I ran the dbcc
shrinkdatabase, it said the size was 14,998 MB and the Space Available is
13,199.89MB.

Here is the results of the command.  We are on SQL 7 sp2 (evaluating sp3)

DBCC execution completed. If DBCC printed error messages, contact your
system administrator.

database_name   database_size      unallocated space
--------------- ------------------ ------------------
MyDB            4764.13 MB         480.81 MB

reserved           data               index_size         unused
------------------ ------------------ ------------------ ------------------
4386112 KB         3709832 KB         654648 KB          21632 KB

Any thoughts?

Marcus



> probably there are deallocated pages that are still being seen as used.
This
> will account for the free size display. The BACKUP on the other hand will
> contain only the allocated pages.
>     There are also bugs related to text page deallocation that have been
> corrected in later SQL70 service packs. So are you on the latest service
> pack too?

> --
> Umachandar Jayachandran
> SQL Resources at http://www.umachandar.com/resources.htm
> ( Please reply only to newsgroup. )