On Tue, Jul 1, 2008 at 5:18 PM, Jeffrey Baker <jwbaker@xxxxxxxxx> wrote: > I recently got my hands on a device called ioDrive from a company > called Fusion-io. The ioDrive is essentially 80GB of flash on a PCI > card. [...] > Service Time Percentile, millis > R/W TPS R-O TPS 50th 80th 90th 95th > RAID 182 673 18 32 42 64 > Fusion 971 4792 8 9 10 11 Essentially the same benchmark, but on a quad Xeon 2GHz with 3GB main memory, and the scale factor of 300. Really all we learn from this exercise is the sheer futility of throwing CPU at PostgreSQL. R/W TPS: 1168 R-O TPS: 6877 Quadrupling the CPU resources and tripling the RAM results in a 20% or 44% performance increase on read/write and read-only loads, respectively. The system loafs along with 2-3 CPUs completely idle, although oddly iowait is 0%. I think the system is constrained by context switch, which is tens of thousands per second. This is a problem with the ioDrive software, not with pg. Someone asked for bonnie++ output: Block output: 495MB/s, 81% CPU Block input: 676MB/s, 93% CPU Block rewrite: 262MB/s, 59% CPU Pretty respectable. In the same ballpark as an HP MSA70 + P800 with 25 spindles. -jwb
