In Virtual SAN 6.2, we introduced key space efficiency features such as Deduplication, Compression, using a four-node All Flash cluster with (4) SQL Servers, a one 200GB database was created with Benchmark Factory for Databases with TPC-E configuration, and a four node AlwaysOn Availability Group was created afterwards. Given this SQL cluster replicates the data to a second, a third and a fourth node for read-only traffic, it's conceivable to measure the deduplication and compression result.
All-Flash Virtual SAN Specifications & Performance
VMware VSAN Disk Group Specification (per Host)
- SSD: 2 x 400GB Solid State Drive (Intel SSDSC2BA40) as Cache SSD
- SSD: 8 x 400GB Solid State Drive (Intel SSDSC2BX40) as Capacity SSD
Windows Server 2012 R2
- Storage Footprint:
- 200GB database: 815GB allocated, 750GB used
- Domain Controller: 100GB allocated, 55GB used
Architecture:
SQL Server Testing Configuration (per VM)
- Windows Server 2012 R2
- Storage Footprint:
- 200GB database: 815GB allocated, 750GB used
- Domain Controller: 100GB allocated, 55GB used
Deduplication and Compression Result:
Server number | Data space usage(GB) | After Deduplication | Saving Times |
Single DB (1 server) | 852 | 392 | 2.17 |
AAG (2 servers) + DC(1) | 1720 | 695 | 2.47 |
AAG(3 servers) + DC (1) | 2430 | 1000 | 2.43 |
AAG(4 servers) +DC(1) | 3140 | 1230 | 2.55 |
Conclusion:
Because VSAN is not aware of application level replicas, therefore more AAG copies may not end up with higher deduplication and compression rate. The space saving rate ranges from 58 percent to 60 percent.