Osiris vs. Microsoft 365 Backup (native)
Microsoft 365 Backup is Microsoft's own first-party backup for SharePoint, OneDrive and Exchange, built into the admin center. It publishes an exact, official per-GB rate. That is worth crediting directly. Most other vendors on this list publish no comparable public list price; MailStore is the exception, with a published starting price (see the MailStore page).
| Fact | Source | Confidence |
|---|---|---|
| Pay-as-you-go, consumption-based pricing. List price: $0.15 per GB per month of protected content. | Pricing model for Microsoft 365 Backup | Confirmed, official |
| Protected storage is the sum of: the live size of OneDrive accounts and SharePoint sites (including the first-stage recycle bin), the live size of protected mailboxes plus their online archives, and deleted/versioned content held for recovery (second-stage recycle bin, deleted or versioned mailbox items). | Same page | Confirmed, official |
| Restore-point frequency does not materially affect cost, and there are no additional Azure API or storage charges beyond the per-GB backup usage fee, even though Azure is used as the payment processor. | Same page | Confirmed, official |
| Deleted or versioned content stops counting toward the bill once it ages out of the backup's recovery window (e.g. 365 days after it was captured). | Same page | Confirmed, official |
| If a partner/ISV product is built on top of the Microsoft 365 Backup Storage platform, the customer is billed only by that partner, not separately by Microsoft. (Acronis's per-GB Microsoft 365 option, covered on its own comparison page, uses exactly this underlying platform.) | Same page | Confirmed, official |
| Storage is Microsoft's own infrastructure by definition. This is Microsoft backing up Microsoft's own service. There is no third-party or customer-controlled storage option, and none is offered. | Consistent with the product's own description; not a separate citation | Confirmed by the nature of the product |
| Not open source: a native, proprietary Microsoft 365 admin-center feature. | Absence checked directly | Confirmed (negative finding) |
| Export format and restore-verification specifics were not researched for this comparison. The scope of this research pass was the pricing model, and this page does not claim an answer either way on those points. | Not researched this pass | Not researched: flagged rather than guessed |
How Osiris differs
Microsoft's own $0.15/GB/month adds up in a direction worth doing the arithmetic on: 1 TB of protected content is $150/month, or $1,800/year, for one tenant, for as long as you keep the data, and that is the transparent, published rate, not a hidden one. Osiris's Business edition is €250 once, with no per-GB meter and no mailbox limit (see pricing), though the currencies differ, and Microsoft's rate includes the storage itself, while with Osiris you separately pay for your own server, storage and the time to operate it; the two numbers are not a direct apples-to-apples total cost of ownership. The more fundamental difference is architectural, not just financial: Microsoft 365 Backup protects you against deletion and corruption inside Microsoft's own service, which is real and useful, but it is not an independent copy outside Microsoft's control the way an export to separate, customer-owned storage is. SeeYour data is your data for why that distinction is the whole point of backing up a SaaS platform in the first place. Osiris is in closed beta and not for sale yet; prices above are planned launch terms.
All facts above from Microsoft's own official documentation, accessed 2026-09-24. Prices and documented behaviour change. Verify current terms directly with Microsoft before deciding. This page is not an endorsement of, or argument against, Microsoft 365 Backup; it states what its own documentation says.