Mr. Worky Workerson, On 10/25/06 5:03 AM, "Worky Workerson" <worky.workerson@xxxxxxxxx> wrote: > However, I am still curious as to the rather slow COPYs from psql to > local disks. Like I mentioned previously, I was only seeing about 5.7 > MB/s (1.8 GB / 330 seconds), where it seemed like others were doing > substantially better. What sorts of things should I look into? It's probable that you have a really poor performing disk configuration. Judging from earlier results, you may only be getting 3 x 5.7 = 17 MB/s of write performance to your disks, which is about 1/4 of a single disk drive. Please run this test and report the time here: 1) Calculate the size of 2x memory in 8KB blocks: # of blocks = 250,000 x memory_in_GB Example: 250,000 x 16GB = 4,000,000 blocks 2) Benchmark the time taken to write 2x RAM sequentially to your disk: time bash -c "dd if=/dev/zero of=bigfile bs=8k count=<# of blocks> && sync" 3) Benchmark the time taken to read same: time dd if=bigfile of=/dev/null bs=8k - Luke
