TamilPHP Code:*********** from the white paper **********
The Oracle Stripe And Mirror Everything (SAME) methodology was used for the database layout for all the tests.
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The white paper did not talk about IO response time which is comprised of waiting time and service time. To optimize I/O performance you must eliminate waiting time and minimize service time.
First of all, SAME is not the best. SAME can eliminate waiting time and will not minimize service time. The SAME has been growing in popularity not for its technical merits, which are few, but because it requires very little DBA skill.
*********** from the white paper **********
10 1Gb Fibre Channel Host Bus Adapters
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My question is: Could any disk be accessed by any controller (HBA)? From the white paper I don’t see it.
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Raw Device based database with multiple DBWR
Without AIO
Medium Workload Heavy Workload
Transaction Throughput 23135 28168
IO throughput 3316 3898
Log_file_parallel_write 9 ms 9 ms
DB_FILE_sequential_read 9 ms 19 ms
CPU utilization 80 % 88 %
With AIO
Medium Workload Heavy Workload
Transaction Throughput 31961 35367
IO throughput 4877 5392
Log_file_parallel_write 4 ms 8 ms
DB_FILE_sequential_read 12 ms 26 ms
CPU utilization 79 % 91 %
In the medium work load the increase in transaction throughput (38 % = 31961-23135/23135*100) with AIO was achieved by spending more time about 3 ms (12 ms -9ms) (or 33 %).
I have a feeling that the increase in db_file_sequential_read wait time was mainly due to SAME methodology because SAME would not minimize service time.
Alternate to SAME is to configure multiple stripe size sets of just few disks. If HP had done the same tests without SAME, the result would have been altogether different.




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