Data Consistency Score (DCS) is a (somewhat) new feature for Office 365 migrations that scores the fidelity of migrated data, allowing admins to identify inconsistencies and integrity issues between ...
Updated May 27, 2021
Version 1.0
Blog Post
16 MIN READ
Migrations with Data Consistency Score (DCS) – more than you ever wanted to know!
Mihai_Grigoruta
Microsoft
Microsoft
Thank you for the interest shown in the new Migration feature DCS. I know the article is a bit long but we wanted to give everyone the possibility to investigate in depth a migration to Office365.
In regards to the corrupt data, I can explain why this can happen:
- Logical corruption on items can be introduced by any app that can access the mailbox, especially in older versions of Exchange
- There is a lot less validation on those versions than newer versions, so while some set of properties on a calendar item might be allowed to be set on an old version, the new version may reject that combination of properties
- Usually these items were corrupted by a 3rd party client of some kind that has put the source data into a logically corrupt state (created meetings without a valid StartDate or similar).
So the corrupt data will be skipped by our system only if you allow the data loss. And not even then the data is not lost because, using this article, you can identify it and back it up on a PST file if that information is really important.
Normally when dealing with corrupt data an Exchange admin would move the mailbox from one database to another or use the New-MailboxRepairRequest command.
Hope this brings more clarity to your journey in data migration 😊