Sizing and Capacity¶
What drives CPU, memory and disk use on the MetaMiner server host for a Fabric and Power BI tenant, and how to set the server memory.
What drives load¶
| Factor | Affects | Why |
|---|---|---|
| Number of workspaces and items | Server memory, client memory, MMDB size | The server builds, and each client holds, an in-memory snapshot of the tenant, including semantic model tables, columns, measures and expressions. |
| Size of workspace scan results | Server memory, network | Scan results for large workspaces can be hundreds of megabytes. The server streams them into the database in parts. |
| Activity volume | MMDB size, disk | Every activity event is stored. Activity events are kept for 104 weeks by default. |
| Capacity Metrics | MMDB size | Hourly capacity, item and storage metrics are kept for 26 weeks by default. |
| Entra directory size | MMDB size, server memory | Users, groups and memberships are stored and loaded for the Entra Users/Groups tab. |
| Number of Power BI environments | Memory, CPU, Microsoft API calls | Each environment has its own collectors. |
| Backups | Disk | Backup archives are stored on the server's archive path. |
| Concurrent client users | Server CPU and memory | Each connected client loads a snapshot and runs its actions on the server. |
Server memory¶
The MetaMiner Server heap is set in the MetaMiner Administrator, Preferences > Settings... > System. The value is written to the Windows service definition and applies at the next server start. The embedded database uses memory outside that heap, so leave room for it and for the operating system.
The server also reserves memory outside the heap for downloading workspace scan results: about 500 MB by default, 2 GB when the heap is larger than 31 GB, and 3 GB when it is larger than 63 GB. Include this reservation when you plan the host's memory.
The MetaMiner Administrator warns you at Start Server if free memory is low compared with the configured heap.
See Memory and JVM.
Disk¶
| Location | Grows with | Default |
|---|---|---|
server\data\mmdb\ |
Metadata, activity events, Capacity Metrics, Entra directory | Inside the installation folder |
| Archive path | Power BI backup archives | Set in the server settings; see How Backup Works |
server\logs\ |
Log retention | Inside the installation folder |
| Java temporary folder | Exports, large downloads | server\javatemp, set on the System settings page |
Use a separate volume for backup archives
If you use backup, point the archive path to a volume with room to grow, or to a UNC share the service account can write to.
Retention keeps the database bounded¶
The server removes old data every Sunday by default. See Data Retention for the settings.
| Data | Default retention |
|---|---|
| Activity events | 104 weeks |
| Capacity Metrics | 26 weeks |
| Archive of deleted items | 180 days |
Sizing table¶
TODO: add measured sizing guidance for Fabric and Power BI tenants
No measured sizing table exists for Power BI. Measure representative tenants (for example 1,000 / 10,000 / 50,000 workspaces, activity events per day, Entra users) and publish heap, host RAM, CPU cores and MMDB disk per tier. Do not reuse the BusinessObjects concurrent-user table.