In ArcGIS Data Store 10.8, scene layer data storage changed to a cluster mode, which allows multiple machines in the tile cache data store. Previous ArcGIS Data Store releases used a primary/standby mode, which allowed only two machines.
Although the cluster mode improves scalability, performance for the cluster mode has proven to be slower than primary/standby mode.
If the tile cache data store contains only one machine, performance is not affected when using ArcGIS Data Store 10.8.
There is an issue in the underlying third-party data storage mechanism used by tile cache data stores. The issue has been reported to the third-party vendor, and they are looking into fixing it. Esri is also looking into implementing workarounds to the problem in a future release.
This issue is associated with a known defect, BUG-000121414.
If your ArcGIS Enterprise deployment contains scene layers, you have a primary and standby tile cache data store, and clustering is not required to accommodate large volumes of scene layer data (more than 200 GB), 10.7.1 is the latest release you should upgrade to at this time.
If you have a tile cache data store on a single machine, this bug will not affect your performance if you upgrade to 10.8.
If you are still encountering this problem after following these steps, please contact Esri Technical Support to resolve this issue.