Determine Trending Variables
With the information recorded as described in the following table it is possible to determine the rate of organization virtual datacenter consumption.
Table 16. Organization Virtual Datacenter Capacity Trending Variables
Variable | Name | Description | Units |
T | Time | Time between points of observation. | Weeks |
NcpuUC | New CPU Units | Total number of CPU units of consumption required for the forecasted virtual machines. | CPU units of consumption |
NmemUC | New Memory Units | Total number of memory units of consumption required for the forecasted virtual machines. | Memory units of consumption |
NVGB | New Storage (GB) | Total amount of storage required for the forecasted virtual machines. | GB |
Tpurchase | Organization Virtual Datacenter Expansion Purchase Time | Amount of time to procure additional organization virtual datacenter resources. | Weeks |
Determining the Trended Growth Rate
Determining the Trend
It is important to understand that the rate of increase dictates how far in advance additional organization virtual datacenter resources need to be purchased. The following table presents a sample virtual machine forecast for a quarter along with sample time-to-purchase value.
Table 17. Sample Organization Virtual Datacenter Trending Information
Attribute | Value |
ΔNcpuUC | 12 |
ΔNmemUC | 12 |
ΔNVGB | 360GB |
Tpurchase | 2 weeks |
NcpuUC,cluster | 320 |
NmemUC,cluster | 717 |
In the following example, NcpuUC,free and NmemUC,free represent the number of free resources within an organization virtual datacenter at which point additional organization virtual datacenter resources should be ordered.
To determine the trigger point for ordering, use the following equation if no pipeline data exists.
Determining Trigger Point for Ordering Capacity Using Trends
For example, from the data provided below, one can calculate the needed free consumption units as listed in the following equation, or 24 units.
For storage, in this example, the trigger point is calculated at 720GB:
