SATA and HDParm

[Peter Teuben]

On Thu, 25 Nov 2004, Ow Mun Heng wrote:

> Guys,
> 
> 	I've heard that hdparm does not run on scsi drives.(SATA included)
> 
> I've tried to use hdparm anyway, and it gave results. But the results
> are seriously _out_of_this_world (for me).
> 
> Can anyone validate these?

try running it successive times. On my SATA i see the disk reads continue
to grow by the amount of the first measurement. I'm also getting an
error message though, 

Timing buffered disk reads:  156 MB in  3.06 seconds =  50.90 MB/sec
Timing buffered disk reads:  302 MB in  3.01 seconds = 100.45 MB/sec
Timing buffered disk reads:  442 MB in  3.02 seconds = 146.19 MB/sec
....
BLKFLSBUF failed: Operation not supported
HDIO_DRIVE_CMD(null) (wait for flush complete) failed: Operation not supported


as if hdparm remembers the buffer it read the last time.... Despite that,
51MB/sec is not bad. But your 146.9 sounds like the 3rd measurement :-)

> 
> /dev/sda:
> Timing buffer-cache reads: 2416 MB in 2.00 seconds = 1208.18 MB/sec
> Timing buffered disk reads: 444 MB in 3.02 seconds = 146.90 MB/sec
> 
> 
> Compared to my Laptop's 80GB (Hitachi) PATA (5400rpm)
> 
> /dev/hda:
> Timing cached reads: 1492 MB in 2.01 seconds = 742.40 MB/sec
> Timing buffered disk reads: 112 MB in 3.04 seconds = 36.85 MB/sec
> 
> 
>