SGA,PGA Estimation oracle database 12c

[satish]

Dear Erman,

We have to build 2 databases in a single server environment. Let's say these are TEST , DEV.Mostly we work on both these databases.we have 64GB RAM on the linux box.we want to use sga_max_size/sga_target for these instances

1)Based on your experiences,could you please let us know an estimation of how much sga_taget and pga_Aggregate_target we should assign for these 2 instances
2)Also i think some ram should be reserved for OS?
3)Is SGA size calculation depends on database size?
4)Is SGA size calculation depends on number of users?

Thanks for all the support

[ErmanArslansOracleBlog]

1)it depends on the volume of data and the type of the workload you are expecting.
2)Yes. For every Oracle Process (LOCAL=NO -- shadow processes) reserve at least 5 MBs. + reserver 1 or 2 GBs for OS processes (root processes)
3)Yes
4)Yes. + workload

[satish]

Thanks for the update erman.

We expect 300 concurrent users and 200GB database size.Is there any rough SGA estimation in this case,when we have 64GB ram on linux server

[ErmanArslansOracleBlog]

200 GB database?

64GB seems ok for the first start..

You may test starting with a 32GB SGA (hugepages enabled) + 10 GB PGA ..

But, this is just a comment..
Without knowing the characteristics of the application, wtihout knowing the workload type and without knowing the data growth trend, this estimation is meaningless.