Why not SCSI?

fross

fross

fross

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Hi all,

I'm reading around, trying to time a good time to buy SSDs, and looking at comparison sites, etc. One thing that dropped out of that was, modern SSDs are almost as fast as the extremely fast server/enterprise level Ultra320 SCSI drives. Which begs the question, why do people not use those anyway?

E.g, Maxtor Atlas 15K II, retails around 300 pounds for the 150Gb version, similar to a quality 128Gb SSD. Its access times are slower of course, being a regular harddrive (but <5ms, very good), however the data throughput is massively higher - 600-700MB/s.

Given the similar price point and high performance, why aren't people looking at these drives for performance, or am I missing something obvious?

Back to waiting for the next gen of SSDs to come out... :)
 
Not sure where you got the data throughput figure from? I can't find anywhere which suggested they are this fast.

But even if they were, you'd have to have a decent SCSI card installed taking up a PCI-X slot. They are a lot bigger, not a issue if you want 1, but when you can get 3 or 4 SSDs and raid0 them for the same price and similar size they don't look so good in comparasion

Even worse is the noise, they are loud. :)
 
Would use SAS now, anyway rather then Parallel SCSI.

73Gbps 2.5" 15000rpm SAS disks can do around 600-800Mbps with 3ms access times each.

However you need a decent (read expensive) SAS Controller to do this which will sit up with a PCI-E x8

The Highpoint Tech 2640 isn't going to get this sort of performance out of the disk.

SAS drives aren't as noisy as the old SCSI but are Enterprise level disks and only really shine in a Server / SAN environment with the Disk Access.
 
Who needs that throughput? Access times is what makes SSDs fast for personal OS use. Throughput is useless for OS stuff over about 70mb/sec. So for applications other than sequential reads/writes, SSDs will wipe the floor with the 15k drives, even if those data throughput figures are correct.
 
SAS drives are expensive, loud, hot, require a new controller and can actually perform worse for single user use than consumer 7200rpm disks.
SSD's are dead silent, dead fast for all roles and have no access times.
 
Thanks for the replies guys.

I think I meant the new SAS drives, and yeah real world 600-700MBps figures around, which is insane. I think there are some stats around concerning how fast they are on random reads, most HDs are in the dust compared to SSDs for those, true.

The drives are comparable prices to SSD per gigabyte, but I've just looked up controllers and they are not cheap, £300+!
 
How does this fit in with motherboards with built in SAS controllers? Once the expense of the card is out, are these drives then worth looking at?
 
unless your machine is going to be switched on 24/7 and will be read/writing constantly at the same time for years on end, you'll never see the benefit, as everyone else has said, their strength comes in the server environment where bulletproof reliability and consistent performance are key - that's what you pay for the security of knowing that it's not going to die on you as a banks' computers are trying to execute 10000 transactions per minute.

SSD's for the home environment are the better solution. Mtron rule the SSD world, and when yu see their figures you understand why, however you don't see them for sale much as you'll **** yourself when you see the price per GB! (the quickest is 560 quid for 32GB!!) but OCZ really aren't that far behind and for the price difference you won't feel the performance difference if you get what I mean!

There's a lot of server and enterprise class stuff being used in the home market at the moment, and to be fair I don't think people really understand that yes there is an advantage, but the true difference is longevity and reliability - we home users change PC's regularly trying to keep up with the latest technology - enterprise doesn't it looks for a long term cost advantage and this comes from knowing that those discs can run flat out 24/7 for say 5 years without missing a beat - that's worth paying through the nose for when a hour down can cost you tens or hundreds of thousands.

Controllers again, yes they do have a performance advantage as they take the loading of the northbridge, but the most powerful ones also have diagnostic and recovery features in them whcih you won't need, and your drives have big caches in them now, so again the margin narrows.

Also server and enterprise class controllers don't really give a damn about power consumption and heat as they are used to living in an air conditioned room that's cooled according solely to their needs. - How many articles have you read about a so and so RAID controller card that's shut down and needed a big cooling mod to make it work... Oh yea but once it was done it was awesome; and yes once you tally up the price you could have bought another SSD and increased your raid array.

Also Fross, when you've heard a Seagate cheetah 15K drive on full chat you'll understand why an ssd is preferable as it clucks and clicks like a bag of bolts - not that noticable in an office but at home its a different story.

Stick to SSD's you'll be gratefull that you did.

Sasahara, the thriughput figures come alive when reading thousands of instructions calling for a read and write simultaneously per second, you won't ever see this in a single user environment, but look at say a bank or online service like ebay's serverfarm and you'll understand the dynamic of how much usage they get.
 
fross said:
Thanks for the replies guys.

I think I meant the new SAS drives, and yeah real world 600-700MBps figures around, which is insane. I think there are some stats around concerning how fast they are on random reads, most HDs are in the dust compared to SSDs for those, true.

The drives are comparable prices to SSD per gigabyte, but I've just looked up controllers and they are not cheap, £300+!
Click to expand...

PERC 5/i is sub-£100 and SAS-compatible.
 
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