Capacity Planning Tool Administration
Fall 2018 Capacity Planning Tool Administration 44th Edition
The Capacity Planning Tool (CPT) provides a framework for collecting business requirements and identifying appropriate network and hardware architecture patterns. The CPT automates the system architecture design loads analysis based on the selected solution architecture.
- Iterative calculations: The factors impacting the system design loads analysis are interdependent, and the model calculations within the CPT are iterative in nature.
- lnvalid design results: RED cells within the CPT Calculator and Design tabs indicate an invalid Design solution normally caused by a system performance bottleneck. CPT configuration must be adjusted to correct the identified performance bottleneck to generate a valid design solution.
- Unstable model calculations: Iterative analysis calculations can become unstable due to improper configuration changes or missing input variables (workflows or server platform selections). RESET selections are included on the CPT Calculator and Design tabs to recover from unstable calculations.
Warning: Formulas supporting the capacity planning analysis are provided by colored cells (formulas in the cells). If you delete or replace formulas in one or more of the colored cells, that functionality will not longer be in the CPT model. If deleting these formulas results in unstable calculations or a workbook crash, you will not be able to recover these formulas using the CPT RESET functions.
Best Practice: Keep an original copy of the CPT for recovery purposes, and save your project workbook often to avoid loss. Keep iterative versions of your CPT Design when you are working on large projects to improve recovery operations.
CPT Circular Reference Error
The system architecture design loads analysis is supported by iterative calculations within the Excel workbook. Several tables within the CPT workbook are used to lookup required performance parameters and provide attributes supporting the overall system design analysis. The CPT recalculates the system architecture design solution when any changes are made in the business requirements or the selected solution architecture.
The Microsoft Excel default configuration does not enable iterative calculations, and sometimes Excel saves to the default configuration. When a default CPT is opened you will receive a circular reference error popup. Figure A-1.1 shows the Excel Circular Reference Error popup that identifies when iterative calculations are not enabled.
Enable iterative calculations
CPT iterative calculations are enabled in the Excel File>options>formula settings. Figure A1-2 shows the proper CPT Calculation options settings.
Best practice: Enable iterative calculations in Excel Options > Formula.
- Maximum Iterations: 500
- Maximum Change: 0.001
Warning: Excel will provide a Circular Reference Warning if the Enable iterative calculations is not selected. Iterative calculations are required for many of the CPT sizing calculations.
CPT Calculator invalid configuration warnings
Several common invalid configuration warnings are shown in cell D7 by the CPT Calculator analysis.
- valid workflow: no warnings were identified by the CPT Calculator analysis.
- Pro not supported: Selected configuration does not support the Desktop Pro selection.
- Workflow targets not available: Software selection not included in the baseline lookup list.
- Platform over capacity: Platform tier over 100% utilization. Remove fixed nodes entry or upgrade platform selection.
- WAN1 Network Saturated: Remote site 1 traffic (cell C13) exceeds available bandwidth (cell G13). Upgrade network bandwidth (cell C13) to resolve issue.
- WAN2 network saturated: Remote site 2 traffic (cell C14) exceeds available bandwidth (cell G14). Upgrade network bandwidth (cell G14) to resolve issue.
- Database platform over capacity. Figure A-1.3 shows Database platform utilization (cell H11) over 100% capacity warning. Increase number of fixed nodes (cell D29) or upgrade platform selection (cell D11).
- Use Design tab for AGD Citrix Fsvc sizing: Citrix feature service workflow is not supported on the Calculator tab. Selected workflow performance targets are available on the Workflow tab Calculator Workflow section, and values can be copy/paste to your project workflow section. Once in project workflows, you can display workflow on the CPT Design tab.
- System overload: Batch process load exceed 3x platform selection capacity.
- AGS Site Capacity unstable: AGS Site (K17) throughput causing unstable site configuration (solution does not scale due to communication overhead). Change cell K17 to Siloed configuration (selection represents single cluster site with internal communications disabled).
In most cases, the invalid configuration can be corrected and the configuration warning will be resolved.
CPT Calculator unstable calculations
CPT Calculator can become unstable if you delete the selected hardware platform from the Hardware lookup table (hardware tab) or the selected workflow (cell E30) from the Workflow tab. In these cases you will get errors in cells throughout the analysis and the CPT may not recover by selecting another hardware platform or another workflow. CPT Calculator RESET selection is provided to recover from these unstable calculations.
CPT Calculator RESET procedure
The CPT Calculator includes a RESET selection at the top of cell E3 which can be used to return the CPT Calculator unstable calculations to a stable state. Once in the RESET state, a valid CPT Calculator configuration can be selected (i.e. selecting a valid platform). Once a valid configuration is selected, cell E3 can be returned to the desired software selection and the CPT Calculator should recover.
CPT Design invalid configuration warnings
There are several configuration selections that can generate invalid results within the CPT Design tab. Invalid selections normally show up as RED cells identified by the CPT Design analysis. RED cells indicate an invalid configuration.
Some of the primary CPT Design invalid configuration warnings include the following:
- Figure A-1.5 shows a configuration warning where workflow network traffic (columns F:G) exceeds available bandwidth (column H). Network contention is identified by RED cells. Increase network bandwidth selection to resolve network contention.
- Figure A-1.6 shows the database platform tier selection (column B) and utilization (column A) cells are RED, and the peak concurrent workflow selections (columns C and D) that access the database tier are RED; this indicates that the database is over capacity. Select a higher capacity database tier platform (column B) or increase the number of database tier fixed nodes (column H) to resolve the performance bottleneck.
Once the configuration is corrected, the CPT Design analysis should show a valid solution.
CPT Design unstable calculations
Some basic configuration problems that generate unstable CPT Design analysis include the following:
- Figure A-1.7 shows results when WTS platform tier was changed from physical to virtual servers while the RESET function (cell T2) was in the ADJUST selection. If a large system load change is made with the CPT Design ADJUST (cell T2) selected the system design analysis can become unstable (many cells showing “#DIV/0!” state. Once the CPT Design is in an unstable condition, you will need to use the CPT Design RESET procedure to recover to a stable state.
- CPT Design analysis will become unstable if you delete one of the selected workflows (column B) from the Workflow tab or one of the selected platforms (column B) from the Hardware tab. Once the CPT Design is in an unstable condition, you will need to use the CPT Design RESET procedure to recover to a stable state.
CPT Design RESET procedure
The CPT Design includes a RESET selection in Cell T2 which can be used to return the CPT Design unstable calculations to a stable state. Make sure that cell D1 is set to Live (not AutoBatch) and select RESET in cell T2. Once in the RESET state, select a valid CPT Design configuration. Once a valid configuration is selected, cell T2 can be returned to the DEFAULT selection and the CPT Design should recover.