How to estimate or calculate downtime for source system export?
As i have two productive system (A+J) and one system (J) , and moving ahead for test migration/export.
ECC - running on oracle 10205 and DB size is 1.8 TB (A+J) - used db size is 1.62 TB
BI - running on oracle 10205 and DB size is 1.2 TB (A+J) - used db size is 980 GB
Portal - running on oracle 10205 and DB size is 45 GB (J). - used db size is 32 GB
Target HP-ux 11.31/Oracle 11202
These estimation is for sorted as well as unsorted export.
Looking forward for your kind response and suggestions.
Downtime estimate has to be calculated by peforming an export.
It cannot be predicted without performing a mock run.However export depends upon many factors.
Server Configuration, Number of Cpus, Memory, Number of R3load process, Tablesplitting.
So i would recommend you to copy the Production data on a similar hardware and perform the export.
Kindly go through the system copy guide as all the steps are mentioned there.
Export Estimation is depend on Number CPU's, RAM and how you tune your database for export.
Based on my experience.
1.6 TB : with 16 cpu's, 32 gb ram and advanced tuning of oracle database (specific for migration), : It took me 6 hrs.
The utilization of cpu was 97 % all time during our export. we have done advance tablespliting and package splitting for large tables.
Defiinetly But this figure will be different in your case if not properly tuned.
I believe 1 more parameter that you should look at is the I/O. If the I/O rate is poor , you may face a lot of issues with the write/read time from the filesystem. Ideally you can use a simple formula for calculating the number of R3load processes you can run - ( No of processors * 3 ) . However any migration is an experiment . You can tune the migration procedure i.e increase/decrease R3load processes during the system copy by looking at the CPU consumption.
Hope this helps a bit,