Why don't 15K Velociraptors Exist?

[Castiel]

Noise? Heat? I know SSD's are the better choice but i'd really love a 1TB 15K Velociraptor for storage.

 

[mv2devnull]

Why? Spinning a spindle at 15k means some serious centrifugal force, so the spindle better be of small in diameter (as is the case for Raptors). And small is lacking in storage space.

600GB 15k SAS is current "top", AFAIK. You can connect those 3TB SATA backup volumes to a SAS controller too.

 

[Castiel]

What kind of access time do 15K SAS drives usually put out? 5.0ms?

 

[Rifter]

I have run a system with 2 SAS 15k drives in RAID 0 and it sounded like 2 cats killing each other under heavy I/O loads, not a good thing for home use. And the access times are indeed around 3-5ms.

 

[Zap]

What I'd love is for the current 600GB VelociRaptor to be sold for $130.

 

[Castiel]

I have run a system with 2 SAS 15k drives in RAID 0 and it sounded like 2 cats killing each other under heavy I/O loads, not a good thing for home use. And the access times are indeed around 3-5ms.

Me Want

 

[bunnyfubbles]

complete waste for just "storage" if anything I specifically search for slower spinning drives for my "storage" needs

I agree with Zap though, there's a place for a 600GB 10KRPM VelociRaptor @ $130, it would be a pretty perfect size for apps and games that don't fit on a SSD, but time for that is running out as the next gen of SSD should halve the cost per GB and bring performance improvements making it even harder to justify investing anything into disc based drives for performance needs

 

[Edrick]

I have run a system with 2 SAS 15k drives in RAID 0 and it sounded like 2 cats killing each other under heavy I/O loads, not a good thing for home use. And the access times are indeed around 3-5ms.

With falling SSD prices and SATA 6Gps, I see no point in 15k drives any longer. Yes they were great for servers for the past decade, but HDDs life is at an end in terms of performance.

 

[HumblePie]

What did you say????

 

[OS]

Why? Spinning a spindle at 15k means some serious centrifugal force, so the spindle better be of small in diameter (as is the case for Raptors). And small is lacking in storage space.

600GB 15k SAS is current "top", AFAIK. You can connect those 3TB SATA backup volumes to a SAS controller too.

i just want to mention supposedly centrifugal force is a myth and misnomer, they beat this down in physics classes, it's supposed to be centripetal force

 

[Voo]

i just want to mention supposedly centrifugal force is a myth and misnomer, they beat this down in physics classes, it's supposed to be centripetal force

Oh goodness that again. Just construct newton's laws in a rotating system and see what happens

But somehow that's one of the few things that everyone takes away from physics classes - I even remember xkcd doing a comic about that a long time ago.

 

[HumblePie]

Oh goodness that again. Just construct newton's laws in a rotating system and see what happens

But somehow that's one of the few things that everyone takes away from physics classes - I even remember xkcd doing a comic about that a long time ago.

What? I didn't catch all of that? What did you say? Were you talking about this XKCD? It was either that or something about how bad your STDs are. Will someone shut off that loud ass 15K raptor please!

 

[Zap]

I agree with Zap though, there's a place for a 600GB 10KRPM VelociRaptor @ $130, it would be a pretty perfect size for apps and games that don't fit on a SSD, but time for that is running out as the next gen of SSD should halve the cost per GB and bring performance improvements making it even harder to justify investing anything into disc based drives for performance needs

We will see when that happens. In the meantime, possibly next gen drive information is out with the new Corsair drive showing up at Newegg and information trickling out about the Intel 510 series drives. Performance does seem to go up, but the $/GB doesn't seem any better than it is right now. Indeed so far it is worse than the current mainstream drives.

 

[Voo]

What? I didn't catch all of that? What did you say? Were you talking about this XKCD? It was either that or something about how bad your STDs are. Will someone shut off that loud ass 15K raptor please!

*catches link before its blown away* Yeah exactly, perfect. Good find (the alt text is pure genius once again) - and hush don't talk about my private.. problems :x

 

[Rifter]

With falling SSD prices and SATA 6Gps, I see no point in 15k drives any longer. Yes they were great for servers for the past decade, but HDDs life is at an end in terms of performance.

I know, thats why i said have run not currently running im very happy with my 120GB intel SSD.

 

[Hacp]

For storage, you want high density platters. If you look at benchmarks, 5400 drives with high density platters beat 7200rpm drives with low density platters. I'm assuming the same is true for 10k vs 7200.

 

[mv2devnull]

i just want to mention supposedly centrifugal force is a myth and misnomer, they beat this down in physics classes, it's supposed to be centripetal force

Sorry, I do know that, but didn't know the "proper english" term. So: the structural integrity of a larger platter could not sustain the centripetal force required for 15k operation?

 

[RaistlinZ]

complete waste for just "storage" if anything I specifically search for slower spinning drives for my "storage" needs

I agree with Zap though, there's a place for a 600GB 10KRPM VelociRaptor @ $130, it would be a pretty perfect size for apps and games that don't fit on a SSD, but time for that is running out as the next gen of SSD should halve the cost per GB and bring performance improvements making it even harder to justify investing anything into disc based drives for performance needs

I agree. There's no point for VelociRaptors for storage needs. Hybrid drives like the Momentum also have dubious value at best, as the cost of SSDs' keep falling.

 

[OS]

Oh goodness that again. Just construct newton's laws in a rotating system and see what happens

But somehow that's one of the few things that everyone takes away from physics classes - I even remember xkcd doing a comic about that a long time ago.

yeah until if the system breaks..and the shards fly in your face... too bad the pieces don't just keep spinning by themselves..

 

[Voo]

yeah until if the system breaks..and the shards fly in your face... too bad the pieces don't just keep spinning by themselves..

So if we give up on the premisse, it doesn't work any longer? Who would've thought that. In reference to a rotating frame you can show a centrifugal force, not more not less - I'm always open if you want to refute that, a little bit mechanics once and again is quite fun (ah though I would prefer not having to check the math in my spare time).

 

[taltamir]

Noise? Heat? I know SSD's are the better choice but i'd really love a 1TB 15K Velociraptor for storage.

15K drives exist, and are expensive.
Raptor was created as a budget enterprise drive... 10K instead of 15K, SATA instead of SAS... it was meant to be an interim card between the desktop 7.2K drives and the 15K enterprise drives, sold to budget conscious enterprises...

Instead it found a niche in the enthusiast market, who were willing to pay extra for speed.

However, at 15K it would be too expensive... and will also have to compete with the other 15K enterprise drives. All of which are already available to anyone willing to pay that price.

The above explanation has also been obsolete (like the raptor itself) for 2 years now... nowadays we have SSDs and any investment in a faster raptor is a total and utter waste of money.

 

[OS]

So if we give up on the premisse, it doesn't work any longer? Who would've thought that. In reference to a rotating frame you can show a centrifugal force, not more not less - I'm always open if you want to refute that, a little bit mechanics once and again is quite fun (ah though I would prefer not having to check the math in my spare time).

it works until it doesn't;

and it's a good thing some people understand the distinction..

 

[Voo]

it works until it doesn't;

So I can just assume that you've got no idea what you're talking about and go on, since I don't get any mechanical or mathematical proofs? Or is your whole point not to object the existance of a centrifugal force? I mean my classical mechanics courses are some time away, but I'm good enough in math, so don't hold back.


@taltamir: What I'm interested in is seeing how the advance of SSDs will influence SAS drives. I'd think we should see slower drives with larger density since fast spinning drives are only really useful to get random access down, which is just obsolete with SSDs.
SSDs for low latency and optimize bandwidth for the HDDs - similar to what we do on the desktop.

 

[taltamir]

in regards to centrifugal and centripetal forces...
Centrifugal force is caused by inertia and a rotating frame of reference rather then a "force" (gravity, electromagnetism, weak/strong nuclear forces) that just magically comes into existence when something spins and pushes outwards... Some physics teachers get really caught up in the semantics of the issue.
Also, it is really, REALLY stupid that two completely different things are called force.

and for that matter, centripetal force is a requirement to have rotational spinning but isn't a real force that magically appears when you spin things either (although a lot of physics teachers fail to make that distinction)... It is either caused by the normal force (covalent bonds resisting compression via electromagnetic force) or tension force (when you pull on something, it resists tearing with a force caused by the covalent bonding/weak interactions (electromagnetic force) between its molecules... up to the point at which it tears). The picture OS showed us is what happens when the materials in question cannot produce enough tension force to counteract the effect of their inertia. They simply tear apart and shred anything around them.

To clarify on centripetal force... Take plate, put water on it, spin it... the water will just fly off because it has neither tension nor normal forcing holding it in place (aka, no "centripetal" force). The plate's molecules are held together by covalent bonds and will not fly apart because it will act to resist shearing... which just so happens to mean it will produce a center facing force.
The reason the water flew out isn't because of a "centrifugal" force that magically materialized. Friction with the plate causes it to gain inertia perpendicular to the plate's outer surface which appears as a force acting "outwards" but isn't, its acting perpendicular which results in outwards motion due to inertia.

@taltamir: What I'm interested in is seeing how the advance of SSDs will influence SAS drives. I'd think we should see slower drives with larger density since fast spinning drives are only really useful to get random access down, which is just obsolete with SSDs.
SSDs for low latency and optimize bandwidth for the HDDs - similar to what we do on the desktop.

pretty much, yes.

 

[OS]

obviously you don't understand the significance of that picture.

that is a jet engine that suffered a rotor burst.

the shredded yellow stuff is a kevlar jacket that catches outward flying shrapnel, which would not be necessary if "centrifugal" force actually existed.


My point is merely that the distinction is not just academic, it does have real world applications.

but i guess if you are not building anything important, like something that might kill people, yes maybe "centrifugal" is good enough.



and before you continue to accuse me of knowing nothing, maybe i have two engineering degrees, BS/MS