Sizing Exadata - Oracle Exadata Recipes: A Problem-Solution Approach - page 113

Finally, take the information collected thus far and map these requirements to disk I/O bandwidth capabilities
on Exadata. The script in Listing 5-14 compares our I/O bandwidth demand from AWR with Exadata I/O bandwidth
capabilities for both High Performance and High Capacity SAS disks, taking into consideration whether you will use
Oracle ASM normal or high redundancy (see Recipe 5-4 for additional details). In Listing 4-14, two additional input
parameters are provided:

•

&asm_redundancy_data is used to multiply the calculated write IOPs by either two or three,
depending on whether normal or high redundancy is used for database files

•

&asm_redundancy_reco is used to multiply the calculated redo IOPs by either two or three,
depending on whether normal or high redundancy is used for redo log files

■ Note please refer to recipe 1-1 to learn more about Exadata I/O bandwidth capabilities.

Listing 5-14. lst05-14-awr-iobw-forexa.sql

SYS @ PROD> select
max(IOPsr) MaxIOPsr,
max(IOPsw) MaxIOPsw,
max(IOPsredo) MaxIOPsredo,
max(Totiops) MaxTotiops,
(case
when max(Totiops) < 10000 then 'Quarter Rack'
when max(Totiops) between 10000 and 25200 then 'Half Rack'
when max(Totiops) between 25200 and 50400 then 'Full Rack'
when max(Totiops) > 50400 then 'Full Rack+'
end) exa_hp,
(case
when max(Totiops) < 6000 then 'Quarter Rack'
when max(Totiops) between 6000 and 14000 then 'Half Rack'
when max(Totiops) between 14000 and 28000 then 'Full Rack'
when max(Totiops) > 28000 then 'Full Rack+'
end) exa_hc
from (
select
(IOPsr + (&&num_addtl_dbs * &&pct_resource_load * &&margin_err * IOPsr)) IOPsr,
(IOPsw + (&&num_addtl_dbs * &&pct_resource_load * &&margin_err * IOPsw)) IOPsw,
(IOPsredo + (&&num_addtl_dbs * &&pct_resource_load * &&margin_err * IOPsredo)) IOPsredo,
(Totiops+ (&&num_addtl_dbs * &&pct_resource_load * &&margin_err * Totiops)) Totiops from (
{ ... Code from Listing 5-11 ... }
)
/
Enter value for num_addtl_dbs: 5
Enter value for pct_resource_load: .5
Enter value for margin_err: 1.25
Enter value for asm_redundancy_data: normal
Enter value for asm_redundancy_reco: high