Home » RDBMS Server » Backup & Recovery » How to determine the rate of block change? (Oracle 10gr2, Windows)
| How to determine the rate of block change? [message #518312] |
Wed, 03 August 2011 01:49  |
kytemanaic
Messages: 55
Registered: February 2009
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Member |
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rdbms:oracle 10gr2
os:windows
with reference to
http://download.oracle.com/docs/cd/B19306_01/backup.102/b14192/bkscenar002.htm#sthref801
Quote:
A.2.2 Writing Backup Scripts for Disk and Tape Scenarios
As in the disk-only scenarios, the backup scripts in this section are categorized based on database workload.
as stated very clearly it depends on the workload, more precisely the rate of block change.
The size of the database can be found out based on formula from http://www.orafaq.com/wiki/Oracle_database_FAQ#How_do_I_find_the_overall_database_size.3F
so how would I know the rate of block change in order to know which script is suitable for me?
I try to find out the rate of block change for the database based on change tracking file but based on
http://download.oracle.com/docs/cd/B19306_01/backup.102/b14192/bkup004.htm#sthref424
Quote:
The size of the change tracking file is proportional to the size of the database and the number of enabled threads of redo. The size is not related to the frequency of updates to the database.
So how do I determine the rate of change? can the rate of block change based on size of archive logs?
I have the following information with me:
starting from 5/10/2011 0101
ending 5/18/2011 1114
this constitute to 9.5 days
F:\recover_area>dir/w
1644 File(s) 27,942,770,176 bytes
2 Dir(s) 10,019,270,656 bytes free
average size of each file 27,942,770,176/1644
=16996818.841849148418491484184915
average size of each day's log = 27,942,770,176/9.5
=2941344229.0526315789473684210526
about 3G
If I have a database size of 92G, based on the archive log size of about 3G per day, can I conclude that a change of 3G/92G is considered as few block change?
thanks a lot!
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| Re: How to determine the rate of block change? [message #518328 is a reply to message #518312] |
Wed, 03 August 2011 03:10  |
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Michel Cadot
Messages: 68757
Registered: March 2007
Location: Saint-Maur, France, https...
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Senior Member
Account Moderator |
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The best way to determine if BCT is good for you is to make tests.
0/ From a representative test database take a full backup
1/ Without BCT, , execute some workload you usually have during a day, make an incremental backup, taking the time for each part
2/ Restore the databasse
3/ Activate the BCT, do the same thing
4/ Compare the times
Regards
Michel
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