Mr. Worky, On 10/25/06 11:26 AM, "Worky Workerson" <worky.workerson@xxxxxxxxx> wrote: > And here are the dd results for 16GB RAM, i.e. 4,000,000 8K blocks: So, if we divide 32,000 MB by the real time, we get: /home (WAL): 53 MB/s write 84 MB/s read /data (data): 89 MB/s write 38 MB/s read The write and read speeds on /home look like a single disk drive, which is not good if you have more drives in a RAID. OTOH, it should be sufficient for WAL writing and you should think that the COPY speed won't be limited by WAL. The read speed on your /data volume is awful to the point where you should consider it broken and find a fix. A quick comparison: the same number on a 16 drive internal SATA array with 7200 RPM disks gets 950 MB/s read, about 25 times faster for about 1/4 the price. But again, this may not have anything to do with the speed of your COPY statements. Can you provide about 10 seconds worth of "vmstat 1" while running your COPY so we can get a global view of the I/O and CPU? - Luke
