SATA II transfer rates

[Thomas Kaiser]

Scott J. Henson wrote:

>Off disk transfer rate is dominated by platter speed, aka the rpms.  For
>a 7000rpm disk, ~55MB/sec is a good transfer rate.  What SATA 2 gives
>you is amazing transfer rate out of cache.  You can test this with the
>-T option.  If I remember correctly, this should be on the order of
>300MB/sec.  It sounds like your disk is operating as intended. 
>  
>
With the -T option I get high values :-)

hdparm -T /dev/sda

/dev/sda:
 Timing cached reads:   2456 MB in  2.00 seconds = 1227.57 MB/sec

So, that means if the block which get read is cached we have a high 
transfer rate, but If it has to be get from the disk we are stuck at 
about ~ 55MB/sec.

Thomas