Active/active without sharding is not a horizontal scaling model, and the blast radius of a fault is wide. One can have GLBs that do routing. So long as the te

Active/active without sharding is not a horizontal scaling model, and the blast radius of a fault is wide. One can have GLBs that do routing. So long as the tenant-to-cell routing tables are consistent, it works fine. And those mappings tend not to change frequently.