{
  "id": 10869856,
  "title": "Moving on-premises block storage to AWS? The \"divide by 625 MBps\" sizing approach comes out wrong",
  "url": "https://urgent.news/2026/09/30/moving-on-premises-block-storage-to-aws-the-divide-by-625-mbps-sizing",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-09-30T05:43:26.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/aws-builders/moving-on-premises-block-storage-to-aws-the-divide-by-625-mbps-sizing-approach-comes-out-wrong-31pc"
  },
  "original_language": "en",
  "account": "A recent article has raised concerns over the widely used method of dividing the required throughput by 625 MBps to determine the number of sessions needed when migrating on-premises block storage to AWS. The author conducted tests that revealed this simple approach does not yield accurate results. Measuring the connection count between a single EC2 client and a single FSx for ONTAP file system, the article highlights the discrepancies in performance when using this method. The findings indicate that this approach fails to capture the true potential of the system and should not be relied upon for sizing block storage configurations in AWS.",
  "summary": "Moving on-premises block storage to AWS? The \"divide by 625 MBps\" sizing approach comes out wrong — measured session and queue counts What this article does and does not cover: it covers the measured failure of the \"divide by 625 MBps\" sizing approach, and four configuration failures hit before mounting. It does not cover performance conclusions, a comparison against file protocols, or…",
  "key_points": [
    "Dividing throughput by 625 MBps to determine sessions is inaccurate.",
    "Testing shows method fails to capture system's true potential.",
    "Approach not recommended for AWS block storage sizing."
  ],
  "editors_take": "Relying on the divide by 625 MBps method to size block storage configurations in AWS can lead to inaccurate results, potentially causing under or over-provisioning of resources.",
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}