Re: tools to improve harddisk performance by short-stroking?

[Ron Johnson <ron.l.johnson@cox.net>]

On 10/07/2010 10:06 AM, Zhang Weiwu wrote:
> Thanks to the national holiday (Beijing) I begin to read some article
> marked for free-time reading a few years ago. One of them is short stroking.
>
> http://www.tomshardware.com/reviews/short-stroking-hdd,2157.html
>
> The article is awfully long just to give a simple idea: by only using
> the first 20% of hard disk space you get about 3 to 4 times of hard-disk
> performance gain. The less you use your hard disk space, the more
> performance gain you get, you can get as much as 5 times faster HDD by
> using less than 10% of hard-disk.
>
> The article says, the only disadvantage of this method is you don't use
> the rest of the hard disk.
>
> Finish reading the article it makes obvious to me that, if this
> "technology" is really so powerful, it should have already been
> implemented in OSes, like Linux, without necessarily abandoning the slow
> part of hard-disk space but instead put rarely used data there.

That's "disk file location optimization".

> Technically it cannot be too difficult to design file system tools in
> the way that it tends to put rarely-accessed files to the end of the
> partition that holds the file system.

Says who?

You'd need to add accounting complexity to the kernel (where would 
it put the accounting data?), and some utility would have to "know" 
the intimate details of your h/w (JBOD, fraction of a JBOD, lvm, 
RAID, what kind of RAID, how many spindles, etc, etc) and determine, 
on multi-drive devices like RAID and lvm, what exactly is the 
*interior* of a drive?

It's a *really* complicated problem.

--
Seek truth from facts.