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Short Stroking Hard Disks for Performance

Less is more. More performance, that is. Learn how to use less of your hard drive (even though you paid for all of it) to get an I/O boost.

Comments on "Short Stroking Hard Disks for Performance"

lbevanda

I think your disk’s short strokes affect your sound card…

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laytonjb

@lbevanda,

LOL! Sorry about that. I’m not sure what happened. I guess you can blame Windows for that :)

Jeff

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lbevanda

@laytonjb,

no matter, very interesting post…

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smuchai

Hi,
Very interesting post.

Where one needs to use the entire disk, or most of it, I guess it would also help to use partitions on the outer cylinders for many small, frequently-accessed files? For example a partition for a squid web cache, or a mail server, and log files.

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benrussousa

Thanks for contributing to a webzine that I read regularly.
And for taking the effort to make a good video (even if it did have a little static) ;-)

It seems to me that you are suggesting that you can reduce average read latency from 12ms to 8ms by using the outer 5% of the disk cylinders.

I don’t think you are correct. I think that your findings are artifacts of the testing method.

First your inner 25% of cylinders was 9.91 ms for ONE test.
And your outer 25% of cylinders was 9.53 ms for ONE test.
Less than 5% difference for inner/outer cylinders and with only one sample test that isn’t convincing. What if your system had some other process wake up for a fraction of one second during the test?

It would be much more convincing if you ran that test for a period of 3000 seconds on a in run level 1 with no kernel device drivers loaded except necessary to get to the console.

Also…. I think that the importance of any performance gains noted by this method are not as real as you might think. In the period of 30 seconds in the first test with 12.37ms seek time you had a total of somewhere around 2,500 random seeks on a drive with 60,801 cylinders. That means that there is about 24:1 odds that each random seek will involve a head seek and not just rotational latency.

Whereas… If you run the same 30 second test on a partition with only 15,000 cylinders, then the odds are only 6:1 that each random seek will involve a head seek and not just rotational latency.

Therefore I don’t think there is any substantial difference in the performance of any cylinders…. Just by a disk with less cylinders or stripe your data across two smaller disks instead of one. Much more cost effective and much bigger bang for your buck than buying standard size cheap disk and getting a “perceived” 25% improvement in a statistic.

I think that your evidence is much more in favor of making sure that you defragment your disk so that your DBF file or your

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stevemadere

I really enjoy reading Linux Magazine articles and
I find them very useful in my work.

However, I think it would be a good idea for you to stick to
the text medium.

I don’t have time to watch an entire video, and I can’t
scan it for relevant information. I imagine the highest
value segment or your audience are all under similar time
constraints.

It’s very important for the magazine’s prospects that
Linux Magazine remain useful to technology professionals
working in a business IT context.

Case in point:

About six weeks ago, I found out about Colfax International
from a banner advertisement on one of your articles.

I clicked through from the banner ad on your article
to ColfaxIntl. website.

I then immediately ordered $16k worth of computer
hardware from them.

I told my sales rep at Colfax that I had found out about them from
an ad on your website.

So, it would seem that the advertising supported model
works and advertising supported content providers
should be supremely concerned with what their audience
finds useful.

This kind of attention to the audience’s practical needs
is THE reason that Google dominates the search engine world.

Yahoo was way out in front in 2000 and they sold their audience
like sheep to wolves. Lycos made big beautiful pages
that few users could load in a reasonable amount of time.
The audience left them for Google (where the
home page was under 5kB and results pages under 10kB) in
droves.

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stevemadere

On the topic of the actual content rather than the medium….

Remember that you can also use ALL of the remaining capacity
of the drive for long term backup (of data for which the
primary copy is on a different device unless using RAID6).

As long as you don’t need high performance access to those
outer tracks during your backup process, you’ll never experience
any performance degradation from doing this.

Array

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