> As best I can measure on my hardware, the cost of a nonsequential
> disk read should be estimated at 4 to 5 times the cost of a sequential
> one ---
Same experience here with RS6000 AIX hardware.
450k/s random versus 4Mb/s sequential (16kb block readahead)
Compared with 256kb readahead the factor is even worse.
Like 10Mb/s sequential.
Andreas