AWS Outages: Is North Virginia the Least Reliable AWS Region and Why?

It's a common belief among AWS users that Northern Virginia, also known as US East or N. Virginia (US-East-1), is the region with the least reliability when it comes to uptime.

To verify this, we analyzed the AWS outage history from 2022 across various regions, specifically focusing on whether N. Virginia truly experienced the most downtime.

Subsequently, we examined and validated several theories explaining why N. Virginia tends to have the highest number of outages.

The Data Behind the Study

Our analysis was powered by our product, StatusGator. StatusGator pulls data from official status pages to create an aggregated status page. Leveraging this unique dataset, we were able to gauge the reliability of different AWS Regions throughout the year 2022, from January 1 to December 31.

It's important to note that the official status pages only report on widespread AWS outages, but this data still provides insight into which regions experience the most significant incidents.

For this analysis, we omitted the GovCloud Regions: US-East and US-West, as these are not accessible to the general public.

AWS Regions by the Number of Outages and Duration in 2022

REGION	NUMBER OF OUTAGES	DURATION
N. Virginia	23	61:07:00
Oregon	5	7:00:00
Ohio	4	4:25:00
Singapore	2	2:15:00
Seoul	2	1:35:00
Ireland	1	0:25:00
Frankfurt	1	3:05:00
London	1	3:10:00
Mumbai	1	0:20:00
Stockholm	1	0:20:00
Sao Paulo	1	0:35:00
Cape Town	1	2:55:00
Milan	1	0:35:00
UAE	1	0:25:00
Sydney	0	0:00:00
Tokyo	0	0:00:00
Montreal	0	0:00:00
N. California	0	0:00:00
Paris	0	0:00:00
Hong Kong	0	0:00:00
Bahrain	0	0:00:00
Osaka	0	0:00:00
Jakarta	0	0:00:00
Zurich	0	0:00:00
Hyderabad	0	0:00:00
Spain	0	0:00:00
Melbourne	0	0:00:00

N. Virginia emerged as the most unreliable AWS Region, topping the list with a total of 23 partial outages in 2022, which collectively lasted for 61 hours and 7 minutes.

Interestingly, the situation appears to be consistent with 2021, indicating that N. Virginia continues to be the region with the least reliability.

Why Is N.Virginia the Least Reliable AWS Region?

We delved into the top three theories popular among AWS users to investigate the reasons behind Northern Virginia's reputation as the least reliable AWS Region.

Assumption 1: Northern Virginia Region Has More Services

The assumption is that the Northern Virginia Region has more services, and consequently, more things can go wrong.

To examine this, we compared the number of services provided by different regions and their corresponding outage records. 

Indeed, N. Virginia leads with the highest number of services - 215, followed closely by Oregon with 207 services, and Ireland with 204.

However, the service count difference among these top three regions is marginal, making it unlikely that just a few extra services are the root cause of N. Virginia's frequent downtime.

Upon reviewing the top five AWS Regions in terms of service offerings, we found no clear correlation between the number of services and the frequency of outages.

If the theory held, Oregon and Ireland, both being large service providers, should have experienced more outages. Yet, Oregon recorded only 5 outages and Ireland just 1 in 2022. Further supporting this, Sydney and Tokyo, the fifth and sixth largest regions, reported zero outages in 2022.

Conclusion: Our analysis suggests that the first assumption is likely incorrect. The number of services available in N. Virginia is not much bigger compared to other AWS Regions to explain the difference in outages.

Assumption 2: Northern Virginia is the Largest and Most Used Region

Some users believe N. Virginia is the most popular region and is heavily loaded with customers running numerous operations simultaneously.

To test this theory, we examined the number of StatusGator users who actively monitor the status of various AWS Regions.

Our data reveals that N. Virginia is the most closely watched AWS Region, suggesting a larger user base compared to other regions.

The user counts monitoring N. Virginia surpasses that of the second-largest region, Oregon, by 189%, and exceeds the third-largest region, Ohio, by 214%.

Conclusion: There's a high probability that the second assumption is accurate. Given the larger number of users keeping tabs on N. Virginia, it's plausible that this region accommodates more customers operating its services simultaneously, leading to potential overloads.

Assumption 3: Northern Virginia Is the First Region, and Was Set Up Differently

Some people think that N. Virginia, as the first AWS Region, might be set up uniquely.

We're not sure if N. Virginia's setup makes it less reliable, and we wonder why AWS hasn't fixed it if other setups work better.

We could guess that because there are so many users in N. Virginia, AWS doesn't want to make big changes. But we don't have enough information to prove this third guess.

Conclusion: We can't be sure about this third guess, but we think it's probably not right. If it was right, then why hasn't AWS made it better?

Summary

We confirmed that us-east-1 (N. Virginia) remains the least reliable AWS Region in 2022.

We saw N. Virginia contributed 51.11% of the total number of outages across the AWS Regions.

As for duration, 68% share of the outage duration belonged to the Northern Virginia Region.

We saw that more users watch the status of N. Virginia. Specifically, 189% more compared to the Oregon Region, and 214% more – compared to Ohio.

Based on this, it is likely that N. Virginia is catering to the highest number of users and has the largest capacity.