VMware vFabric Postgres (vPostgres) 9.2 improves vertical scalability over the previous version by 300% for pgbench SELECT-only (a common read-only OLTP workload) and by 100% for pgbench (a common read/write OLTP workload). vPostgres 9.2 on vSphere 5.1 achieves equal-to-native vertical scalability on a 32-core machine.
Using out-of-the-box settings for both vPostgres and vSphere, virtual machine (VM)-based database consolidation performs on par with alternative approaches (such as consolidated on one vPostgres server instance or consolidated on multiple vPostgres server instances but one operating system instance) in a baseline memory-undercommitted situation for a standard OLTP workload (using dbt2 benchmark, an open-source fair implementation of TPC-C); while performs increasingly more robust as memory overcommitment escalates (200% better than alternatives under a 55% memory-overcommitted situation).
By using an unconventionally larger database shared buffers (75% of memory size rather than the conventional 25%), vPostgres can attain both better performance (12% better) and more consistent performance (70% less temporal variation).
When using an unconventionally larger database shared buffers, the vPostgres database memory ballooning technique can enhance the robustness of VM-based database consolidation: under a 55% memory-overcommitted situation, using its help can advance the performance advantage of VM-based consolidation over alternatives from 60% to 140%.
For more details including experimentation methodology and references, please read the namesake whitepaper.