Custom Metadata types data limit

See Custom Metadata Limits:

Custom metadata per organization * - 10 MB

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* Record size is based on the maximum field size of each field type, not the actual storage that’s used in each field. When adding fields to a custom metadata record, use the appropriate type and specify a length that doesn’t exceed what’s needed for your data. This action helps you avoid reaching the cached data limit. For example, if you create a US social security number (SSN) field, select the Text data type and specify a length of 9. If instead you selected Text Area, the field would add 255 characters to the usage count for each record, regardless of the number of characters entered.

Here is a screenshot of that page:

It's interesting that Salesforce is now encouraging everyone to migrate to Custom Metadata. So much so that they have a setting to allow you to turn off LIST Custom Settings now (Schema Settings). But with a limit of 100 TOTAL types (packages and local), this is just unreasonable. We have almost 100 Custom Metadata Types already and still have almost 300 Custom Settings we'd like to migrate. Until Salesforce extends the NUMBER of Custom Metadata Types (and total size), we won't be able to.

The number of custom metadata types per org has been increased to 200, and the limit is no longer in size but is 10 million characters total across all unmanaged metadata types in the org

https://help.salesforce.com/articleView?id=custommetadatatypes_limits.htm&type=5