CPU Estimates for Secure Transactions

This section continues the example deployment to illustrate how to calculate CPU requirements for a theoretical use case that includes both secure and nonsecure transactions.

To estimate the CPU requirements for secure transactions, make the following calculations:

1. Start with a baseline figure for the CPU estimates (as illustrated in the previous section, Example Estimating Processor Requirements).

2. Calculate the percentage of transactions that require secure transport, and calculate the CPU estimates for the secure transactions.

3. Calculate reduced CPU estimates for non-secure transactions.

4. Tally the secure estimate and nonsecure estimate to calculate the total CPU estimates.

5. Round up the total CPU estimate to an even number.

CPU Estimates for Secure Transactions shows an example calculation based on use cases and usage analysis for the Portal Server that assume the following:

• All logins require secure authentication.

• All logins account for 10% of the total Portal Server load.

• The performance requirement for secure transactions is the same as the performance requirement for non-secure transactions.

  To account for the extra computing power to handle secure transactions, the number of CPUs to handle these transactions will be increased by a factor of four. As with other CPU figures in the example, this factor is arbitrary and is for illustration purposes only.

Table 5–5 Modifying CPU Estimates for Secure Transactions

Step	Description	Calculation	Result
1	Start with baseline estimate for all Portal Server transactions.	Baseline estimate from Study Use Cases for Peak Load Usage is 4 CPUs.	- - - - -
2	Calculate additional CPU estimates for secure transactions. Assume secure transactions require four times the CPU power as nonsecure transactions.	Ten percent of the baseline estimate require secure transport:    0.10 x 4 CPUs = 0.4 CPUs   Increase CPU power for secure transactions by a factor of four:    4 x 0.4 = 1.6 CPUs	1.6 CPUs
3	Calculate reduced CPU estimates for nonsecure transactions.	Ninety percent of the baseline estimate are non-secure:    0.9 x 4 CPUs = 3.6 CPUs	3.6 CPUs
4	Calculate adjusted total CPU estimates for secure and nonsecure transactions.	Secure estimate + non-secure estimate = total:    1.6 CPUs + 3.6 CPUs = 5.2 CPUs	5.2 CPUs
5	Round up to even number.	5.2 CPUs ==> 6 CPUs	6 CPUs

From the calculations for secure transactions in this example, you would modify the total CPU estimates in CPU Estimates for Secure Transactions by adding an additional two CPUs and four gigabytes of memory to get the following total for Portal Server.

Component	CPUs	Memory
Portal Server	6	12 GB