We recently built a new server for our Production database. The machine is top of the line with 128GB of RAM, dual E5-2650. We also included NVME drives for ZIL and L2ARC. Currently we have 3 zpools. First one holds the FreeBSD install. Second holds the jails, and third holds all of the database data. Needless to say it's fast.
Here is the problem. I am running benchmarks using pgbench-tools. I have been running the tpc-b test. When I have the ZIL drive attached to the zpool, the transactions per second average out at 220. When I disable the ZIL drive, transactions per second average out at 700.
Anybody ever experience this? I understand the use of the external ZIL drive for data protection, but with PostgreSQL is it really needed? The performance hit is pretty big. My next test is loading up the machine with a copy of our Production data and seeing how some transactions behave with it enabled and disabled.
I've included a copy of one of the tests done.
Thanks,
-Joseph Kregloh
