On Thu, Feb 07, 2008 at 01:31:16AM +0100, Keld Jørn Simonsen wrote: > Anyway, why does a SATA-II drive not deliver something like 300 MB/s? Wait, are you talking about a *single* drive? In that case, it seems you are confusing the interface speed (300MB/s) with the mechanical read speed (80MB/s). If you are asking why is a single drive limited to 80 MB/s, I guess it's a problem of mechanics. Even with NCQ or big readahead settings, ~80-~100 MB/s is the highest I've seen on 7200 RPM drives. And yes, there is no wait until the CPU processes the current data until the drive reads the next data; drives have a builtin read-ahead mechanism. Honestly, I have 10x as many problems with the low random I/O throughput rather than with the (high, IMHO) sequential I/O speed. regards, iustin - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
