Setting harddisk 'read ahead' values in Ubuntu

Here is a snippet from a Ubuntu forums post...I found that setting my read ahead value to 1024 (it was 256 by default) gave me the best directory to directory file transfer speeds testing on the same 2.4 gigs of files, copying from one directory to another, same ext4 partition. Does anyone have any further information or testing on this?

_______from Ubuntu forums below________

My hard drive is a Western Digital 500Gb Eco Green something. (The name doesn't really say "I'm fast")


Anyway, here is what I did to increase my performance:

I changed the "read ahead" for the disk.

For example, the following will get your current read ahead value:
Code:

Code:

sudo blockdev --getra /dev/sda

Mine said 256 at first so I changed it to
Code:

Code:

sudo blockdev --setra 65536 /dev/sda

Experimented with different values for this to get much better transfer rates (4096, 16384, 32768, 65536, 131072, 262144).

By doing this I got my Mp3 transfer up from 3Mb/s to 6-10 Mb/s. Large file copy increased from 8-15 Mb/s up to 24 Mb/s.

Hope this information helps!

 

Laptop Mode Tools has a readahead option.