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by
Zsolt Kerekes,
editor - May 29, 2008 |
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How Much Hay Has Your Car Been Eating Lately?
I've been publishing
articles about the
SSD market since the
1990s -
so maybe that's why something in my brain snapped yesterday when I was reading
yet another new article from an SSD vendor about the server acceleration
which you could get from their product.
Because the only competition it
mentioned was
hard drives.
Enough
is enough! - I said. |
I can't remember whether the article claimed
their product was 300x or 500x faster in
random IOPS
than a 15K
SAS hard drive -
but as the IOPS in a hard drive haven't changed much since the appearance of the
first 15K RPM products in
EMC's CLARiiON
systems in 2002, and as there may
never
be a 20K RPM drive... The long and the short of it is that every month the
fastest SSDs get
better - while the fastest hard drives remain exactly as fast as they were. So
the HDD versus SSD random IOPS gap gets wider. We haven't learned anything
new!
I'm not denying that these comparisons have been useful in the
past. And they are still useful when a single
2.5" SSD for
example is being compared with a single 2.5" hard drive. But as I wrote in
an article in
2003 when you're looking at what a fast
rackmount SSD can
do for you - you should be calculating how many servers you can save /
or would need to add to get to the same 3x application speedup - not how
many disks.
It's understandable that people refer new products to an
assumed common frame of reference.
I'm sure that a century ago when
the first car owners were talking to their neighbors - they must have made
comparisons like - how much faster they were than a horse.
"It's
amazing. Unlike my old horse my new car doesn't get tired. And I don't need
pasture or hay to make it go - just a few bottles of gas."
And
you didn't get the same stinking mess in the city streets either. (At the time
the Sherlock Holmes stories were being published in the Strand Magazine in 1892
- there was a "green" market carting horse dung out of London to stop
the streets becoming impassable.)
I think I'm safe in assuming that the
last time you bought a car - you didn't compare its speed or fuel consumption
to a horse. Am I right?
Of course you didn't. You compared it to
other cars!
It's a sign of a maturing market when there are enough
products around to compare them to each other, instead of comparing them to
what came before. And we have reached that time with SSDs. It's taken
30 years
- but that's another story.
This new wave of comparing SSDs to each
other kicked off with the article
RAM SSDs versus
Flash SSDs - which is Best? - which included views from leading SSD
oems on both sides of the fence. And other articles have demolished the
myths about SLC
flash SSDs while highlighting the
risks of using
MLC flash in inappropriate server applications.
In my view
comparing SSDs to HDDs does not give you a useful picture when you're looking
at options in the server acceleration market.
Although I expect that
such weak comparisons will be sprinkled in lite weight SSD articles for the
next few years - it's time for some stronger seasoning. It's time for more
articles by SSD vendors to say how their products and technologies compare
with other SSDs. |
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| ...Later:- some companies are still doing
it...
..In contrast - here's
a fact filled vendor-neutral white paper (published November 2008) - which
provides useful measurements and comparisons...
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Will Hard
Disks Get Faster?
Hard road ahead
for hard drives?
top 100 articles and
blogs about SSDs
How will hard drives
fare in an SSD world?
Recovering Data
from Drowned / Flooded Hard Drives
comparing the SSD
market today to earlier tech disruptions
You're never more than 20
feet away from a rat (or hard drive)
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| "You're telling
them how - with your technology they can timeshare 3 users on a
Wang wordprocessing workstation.
Mentally they already see themselves as ditching Wang and buying an
Apple or
(later) IBM PC." |
| ...Editor:- talking to
an SSD company (Oct 2011) about why they should stop using outmoded hard disk
comparisons in their marketing communications. | | |
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| the Problem with
Write IOPS in flash SSDs |
Random "write IOPS"
in many of the fastest
flash SSDs are now similar to "read IOPS" - implying a
performance symmetry which was once believed to be impossible.
So why
are flash SSD IOPS such a poor predictor of application performance? And why
are users still buying
RAM SSDs which cost an
order of magnitude more than SLC? (let alone
MLC) - even
when the IOPS specs look superficially similar?
This article
tells you why the specs got faster - but the applications didn't. |
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And why competing SSDs with
apparently identical benchmark results can perform completely differently.
...read the
article | | | |
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