Question

Difficulty: Very hardEstimating GCP Costs with the Pricing Calculator

A cloud engineer is configuring a cost estimate in the Google Cloud Pricing Calculator for a high-availability database cluster operating continuously in `us-central1` for a 730730-hour month.

The target architecture consists of the following components:
1. Compute Engine: 1010 `custom-2-8` VM instances (each with 22 vCPUs and 8 GB8\text{ GB} of RAM).
- Base rate per vCPU: $0.033174\$0.033174 per hour.
- Base rate per GB RAM: $0.004446\$0.004446 per hour.
- Sustained Use Discount (SUD): Instances run 100%100\% of the month, qualifying for an effective 30%30\% discount on total compute costs (0.700.70 multiplier).
2. Storage: Each of the 1010 instances uses a 200 GB200\text{ GB} Extreme Persistent Disk (`pd-extreme`) provisioned with 2,500 IOPS2,500\text{ IOPS} per disk.
- Capacity rate: $0.125\$0.125 per GB per month.
- Provisioned IOPS rate: $0.025\$0.025 per provisioned IOPS per month.
3. Network Egress: Total internet data egress from `us-central1` to North America is 500 GB500\text{ GB} per month.
- First 100 GB100\text{ GB} per month: $0.00\$0.00 per GB (free tier).
- Next 400 GB400\text{ GB} (101 GB101\text{ GB} to 500 GB500\text{ GB}): $0.12\$0.12 per GB.

What is the net total monthly cost in USD for this workload? (Round your final answer to two decimal places.)

Answer: 1443.79 USD

Answer

The net total monthly cost for the specified infrastructure components is 1443.791443.79 USD.
The correct result of 1443.79USDisderivedbyaccuratelycombining:(1)discountedcomputecosts(1443.79 USD is derived by accurately combining: (1) discounted compute costs ( 743.9868 \times 0.70 = 520.79076 USD),(2)ExtremePersistentDiskstoragecapacity( USD), (2) Extreme Persistent Disk storage capacity ( 250.00 USD)plusprovisionedIOPS( USD) plus provisioned IOPS ( 625.00 USD),and(3)internetegressafterapplyingthe100GBfreetier( USD), and (3) internet egress after applying the 100 GB free tier ( 48.00$ USD).

Step-by-Step Solution

1
Calculate single instance hourly compute rate for vCPU and RAM
Gross hourly rate = (2×$0.033174)+(8×$0.004446)=$0.066348+$0.035568=$0.101916(2 \times \$0.033174) + (8 \times \$0.004446) = \$0.066348 + \$0.035568 = \$0.101916 per hour.
Custom VM pricing evaluates vCPU and memory allocation independently.
2
Calculate gross compute cost for all 10 instances running 730 hours
Gross monthly compute cost = 10×730×$0.101916=$743.986810 \times 730 \times \$0.101916 = \$743.9868.
Monthly compute allocation measures total instance hours before applying sustained usage discounts.
3
Apply Sustained Use Discount (SUD) to compute cost
Net monthly compute cost = $743.9868×(10.30)=$743.9868×0.70=$520.79076\$743.9868 \times (1 - 0.30) = \$743.9868 \times 0.70 = \$520.79076.
N1 and custom workloads running continuously qualify for a 30% effective discount over a 730-hour month.
4
Calculate storage capacity and provisioned IOPS costs for Extreme Persistent Disks
Storage capacity cost = 10×200 GB×$0.125=$250.0010 \times 200\text{ GB} \times \$0.125 = \$250.00. Provisioned IOPS cost = 10×2,500 IOPS×$0.025=$625.0010 \times 2,500\text{ IOPS} \times \$0.025 = \$625.00. Total disk cost = $250.00+$625.00=$875.00\$250.00 + \$625.00 = \$875.00.
Extreme Persistent Disk pricing separates raw disk storage capacity from provisioned IOPS performance.
5
Calculate tier-based egress charges
Net egress cost = (500 GB100 GB)×$0.12=400 GB×$0.12=$48.00(500\text{ GB} - 100\text{ GB}) \times \$0.12 = 400\text{ GB} \times \$0.12 = \$48.00.
The first 100 GB of internet egress per month is free under standard GCP billing rules.
6
Sum compute, storage, and egress components for the total net cost
Total net cost = $520.79076+$875.00+$48.00=$1443.79076$1443.79\$520.79076 + \$875.00 + \$48.00 = \$1443.79076 \approx \$1443.79.
Adding all discounted subcomponents produces the final total estimate.

Key Concept

Estimating GCP Costs with the Pricing Calculator
Estimated Time:3m 0s
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