Re: [gentoo-user] Normal disk speed?

[Volker Armin Hemmann <volkerarmin@googlemail.com>]

On Thursday 30 September 2010, Adam Carter wrote:
> Taring my mp3 collection from 2.5in 500MB internal sata drive (sda) to
> esata 3.5in 500MB drive (sdb) and it seems slow. In vmstat i can see that
> the external drive writes faster than the internal can read (external has
> periods of inactivity)
> # time tar cf /mnt/usbdrive/mp3back.tar mp3/
> 
> real    10m9.679s
> user    0m1.577s
> sys    2m1.769s
> # du -ks mp3/
> 21221661    mp3/
> 
> So 21221MB in 610 seconds = 35 MB/s
> 
> # hdparm -t /dev/sda
> 
> /dev/sda:
>  Timing buffered disk reads:  220 MB in  3.01 seconds =  73.14 MB/sec (77
> with --direct)
> 
> FWIW;
> # hdparm /dev/sda
> 
> /dev/sda:
>  multcount     = 16 (on)
>  IO_support    =  1 (32-bit)
>  readonly      =  0 (off)
>  readahead     = 256 (on)
>  geometry      = 60801/255/63, sectors = 976773168, start = 0
> 
> 
> So the should i expect filesystem (reiser3) and other overhead to cut the
> read performance to less than half of what hdparm reports? Anything else i
> can look at to speed it up? Im using CFQ io scheduler.

as soon as your harddisk seeks you are lucky to be above 5mb/sec. Yes, even 
with a modern harddrive. Just look up the seek times and do the math.

Your harddisk seeks, everything is slow.