RE: tools to improve harddisk performance by short-stroking?
>---- Original Message ----
>Subject: RE: tools to improve harddisk performance by short-stroking?
>Date: Thu, 07 Oct 2010 23:06:52 +0800
>>Thanks to the national holiday (Beijing) I begin to read some
>>marked for free-time reading a few years ago. One of them is short
>>The article is awfully long just to give a simple idea: by only
>>the first 20% of hard disk space you get about 3 to 4 times of
>>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
>>using less than 10% of hard-disk.
>>The article says, the only disadvantage of this method is you don't
>>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
>>part of hard-disk space but instead put rarely used data there.
>>Technically it cannot be too difficult to design file system tools
>>the way that it tends to put rarely-accessed files to the end of the
>>partition that holds the file system. I am sure I have many files on
>>computer with atime a few years ago (e.g. man page for hier; files I
>>moved to Trash a few years ago), they can be moved to the bottom of
>>space with a performance gain.
>>Since the knowledge seems to be decades old (some references to this
>>idea are in 1990s under different names), if the article's
>>many-time-hdd-performance-gain is true, in the decade there should
>>already been harddisk performance speedup tool that moves rarely
>>accessed file to the bottom of file system once a week or so and get
>>a 3 time boost of HDD performance.
>>Question is how to find such a tool? A google search for such tool
>>up in vain, that seem to suggest the tool doesn't exist, which means
>>article is probably wrong.
>>Note that I read about methods of partitioning harddisk to get
>>short-stroking advantage, that wouldn't be optimal, because human
>>decide what are frequently accessed files (put them to first
>>and what are rarely accessed files (put them on later partitions),
>>tool can do this thing much better than human. Besides, human doing
>>partition optimization can only choose one of /var, /usr, /home,
>>and "swap" as "rarely accessed", the fact is none of them are rarely
>>accessed, while most of them contain rarely accessed files. That's a
>>very bad granularity compare to what specialized tool could do.
>>Thanks in advance for comments!
Just a guess but the short stroking advantage was likely for disk
access in which the arm returns to some neutral position after
access. OTOH if the access is the usual elevator algorithm in which
the arm stays where it is assuming the next access will be nearby the
short stroking will be ineffective.
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