The hidden costs of Backblaze B2 migration

Egress and pricing cliffs

Backblaze B2 costs $6 per TB per month for storage. While AWS S3 charges $23 per TB for the same volume, B2 has a free egress tier up to three times your average monthly storage. If your archive retrieval exceeds this 3x cap, you pay $0.01 per GB for every extra gigabyte. For a 20TB archive with 60TB of retrieval, you avoid egress charges entirely. I see the advantage for cold archives, but you must model your retrieval patterns carefully. If your workflow requires constant access, the $0.01 per GB fee creates a pricing cliff that negates the low storage price. For high-throughput workloads like AI/ML training, the B2 Overdrive tier costs $15 per TB per month and includes unlimited free egress. Wasabi has a 1:1 egress ratio. This ratio is more favorable for retrieval-heavy workflows than B2’s 3:1 ratio. You should calculate your egress ratio by dividing monthly outbound TB by total stored TB. If you find that your egress is 1000% of your storage, B2’s cost structure will likely fail you. For a 10TB workload with 50TB of egress, AWS S3 costs $6,800 per month, whereas Backblaze B2 costs $1,100. You can mitigate these costs if your destination supports the Bandwidth Alliance, which allows for zero-egress through partners like Cloudflare.

Security and API gaps

The security gap between S3 and B2 is real. Scott Piper, a researcher at Wiz, shows that organizations using S3 clones cannot rely on AWS security assumptions. Most S3-compatible services provide fewer protections and controls than AWS S3 Block Public Access. Additionally, IAM capabilities and semantics differ considerably among different implementations. This difference causes vulnerabilities like unauthorized privilege escalation or broken tenant isolation. You know the basics of S3, so I will skip the API details. However, most S3-compatible providers support only 90% to 95% of the AWS API. You will miss specialized functions like S3 Object Lambda or S3 Select. Furthermore, S3-compatible services often lack the structured access-key formats and secret-scanning support available for AWS. This makes credentials harder for security teams and tools like GitHub to detect. Since B2 has no user-facing interface for media, you must add third-party tools like LucidLink or Iconik to your stack. The storage price savings do not offset the engineering time and security risks of the migration. If you decide to migrate an established AWS data lake to Backblaze B2, you must account for 200 to 400 engineering hours to manage the loss of native IAM-based access from EC2 and Lambda services. This migration task involves updating application configurations and testing access to ensure applications can read and write to the new provider.

Reliability and performance risks

Backblaze reported 36 outages over the past year. On August 10, 2026, users experienced login and image loading issues. These issues affected account access. Another incident on August 25, 2026, caused intermittent upload and download errors in the EU Central region. One maintenance window on August 12, 2026, lasted 2 hours and 20 minutes in the CA East region. A separate maintenance event on August 19, 2026, lasted 13 hours and 50 minutes. Backblaze is the slowest of the three options when compared to Wasabi or iDrive e2. In a test with 15GB of random data in the West US 2 data center, Backblaze reached only 21 MB/s. This is much lower than the 102 MB/s recorded for Wasabi in Virginia. For a 1TB backup, Backblaze took 35 minutes and 41 seconds to upload, whereas AWS S3 took only 15 minutes and 38 seconds. For 1,000,000 PUT requests for a 1TB backup, AWS S3 costs $5.50. Furthermore, the company’s stock value has dropped recently, and the founders are selling stock over the next year. Will the falling stock value impact long-term data reliability?