SCSI drive beginner questions

[Kadence]

I want to build my own computer, and I'm thinking about getting a SCSI drive because then I can get one that's 15000RPM.

Would a SCSI drive fit in a normal PC case? Would it be compatible with a normal CPU and motherboard? I'm assuming I have to buy some sort of adapter for the motherboard, but other than that I shop for parts as normal.

Is installing a SCSI significantly more complicated than an IDE drive?

Can you use a SCSI drive in the same computer as an IDE drive that acts as a secondary drive?

And are there any other quirks about installing and owning a SCSI that are important to know?

 

[Andrew1990]

Remember this, SCSI was built for servers. They are faster in transfering data but are not as great at seek times as a SATA drive. Also, good SCSI Cards are quite expensive.

Otherwise, SCSI hooks up similar to IDE except with a controller card like you said. It uses a ribbon that is a tad bigger than an IDE ribbon. You can use it with an IDE drive as well.

 

[Fullmetal Chocobo]

You might be more interesting in getting a 15k SAS drive. Faster than SCSI without too much more money (if not the same as SCSI).

Honestly though, SAS & SCSI are huge investments, and SCSI can be a pain in the ass if you are new to them. What is this system going to be used for and what is your budget?

 

[Kadence]

It is for a desktop computer. However this is the computer I do all my work on - I pretty much literally spend the entire day on it, so I want something good. I can also do some heavy duty numerical routines on it at times.

How can SCSI be a huge pain in the ass? Is that just for setup, or for beyond that?

What is an SAS drive? I looked it up but didn't quite get it. Is that like a SCSI for desktops instead of servers?

I don't particularly have a budget in mind for the hard disk, though I suppose I'd like to pay $3K for the computer total, but for a real fast setup wouldn't mind going a couple thousand higher. I'll probably be getting 4GB-8GB RAM, and a Core2 quad core 2.5GHz+.

 

[EarthwormJim]

SAS - Serial Attached SCSI, it's the new SCSI spec.

15k rpm drives are not worth it in a single user environment, like your work computer. They're not intended for desktop use, their firmware is just optimized for the kind of uses you'd put it through.

They just aren't, you won't notice the speed improvement beyond a 10k rpm drive. Even a 10k rpm drive can be hard to notice the difference with.

I had a 15k Cheetah, didn't really see a tangible difference in speed. I've had two Raptors, again I didn't see a huge tangible difference in speed. Certainly not enough to justify the cost.

The new Raptor is very fast though for a single user environment, and it's not horribly expensive. If you must spend a lot on a hard drive, then that's where I'd look. But you'd honestly be more than happy with the new 300gb+ platter drives from Samsung and WD.

On top of the hard drive cost, you're going to have to get a good controller card if you go SAS/SCSI. Figure $200+ for that at the very least.

 

[Nothinman]

Remember this, SCSI was built for servers. They are faster in transfering data but are not as great at seek times as a SATA drive. Also, good SCSI Cards are quite expensive.

You have that backwards, because of the higher rotational speeds seek times are a good bit lower than a consumer level drive. I'd worry about the cost of the drive more than the controller.

SCSI can be a pain in the ass if you are new to them.

Not really, termination is handled automatically now so the only real issue is having to feed Windows the drivers during installation and that's a Windows problem and has nothing to with SCSI at all.

 

[Kadence]

So it seems a couple of my main 10000RPM+ choices in the 150GB range are:
WD Raptor SATA 150GB 10000RPM 4.6ms seek ~$250
Seagate Cheetah 15K.5 146GB 15000RPM 3.5ms seek - ~$300+controller

I saw the Cheetah 15K.5 listed in different places under both SAS and SCSI, is it available in both or was that an error and it's just SAS?

At those prices, if not for the controller, the Cheetah would definitely seem like the better buy due to the improved seek.

I have no interest in a RAID or anything, just a vanilla setup; would I really have to shell out $200+ for a controller? And are SAS/SCSI controllers the same thing, or do they require different controllers?

 

[EarthwormJim]

Originally posted by: Kadence
So it seems a couple of my main 10000RPM+ choices in the 150GB range are:
WD Raptor SATA 150GB 10000RPM 4.6ms seek ~$250
Seagate Cheetah 15K.5 146GB 15000RPM 3.5ms seek - ~$300+controller

I saw the Cheetah 15K.5 listed in different places under both SAS and SCSI, is it available in both or was that an error and it's just SAS?

At those prices, if not for the controller, the Cheetah would definitely seem like the better buy due to the improved seek.

I have no interest in a RAID or anything, just a vanilla setup; would I really have to shell out $200+ for a controller? And are SAS/SCSI controllers the same thing, or do they require different controllers?

It's not a better buy because the improved seek times are not going to give you any tangible results in a single user environment, i.e. a desktop computer. I'm speaking from experience, I had a 15k rpm Cheetah drive.

If you must get a 10k rpm drive, look at the new Velociraptor, not the old Raptors. Newer 7200 rpm drives are for the most part faster than the older raptors. Especially at the price you saw, $250 for a 150gb raptor is a horrible price compared to the new raptor:
http://www.newegg.com/Product/...ern+Digital-_-22136260

Which mind you is significantly faster than the older raptors, never mind twice the capacity..

SAS is a serial bus, not a parallel bus like SCSI was. They are not the same thing.

 

[Lorne]

The only reason to go SCSI is that you do major multitasking, IF you have a bunch of programs working (Not just idle in the background and Photoshop and 6 porn downloads at once is not considered multitasking).

Just pick up a Raptor Its fast and cheaper, This is coming from a SCSI enthusiest.

 

[GarfieldtheCat]

Originally posted by: Kadence
So it seems a couple of my main 10000RPM+ choices in the 150GB range are:
WD Raptor SATA 150GB 10000RPM 4.6ms seek ~$250
Seagate Cheetah 15K.5 146GB 15000RPM 3.5ms seek - ~$300+controller

I saw the Cheetah 15K.5 listed in different places under both SAS and SCSI, is it available in both or was that an error and it's just SAS?

At those prices, if not for the controller, the Cheetah would definitely seem like the better buy due to the improved seek.

I have no interest in a RAID or anything, just a vanilla setup; would I really have to shell out $200+ for a controller? And are SAS/SCSI controllers the same thing, or do they require different controllers?

Storagereview link

Here is a chart with the two fatest SATA drives, as well as the two fasted SCSI drives, and a comparision between the 15k.4 and 15k.5

If you look at the single use scores between the seagate models, the newer model has lower scores then the older 15k.4 model. The multi-user scores have gone up. SCSI drives are tweaked for multi-user performance, and single user performance will suffer.

For single user tasks, the VRaptor wins 3/5, and the other two are only a couple of percent difference. The Vraptor is also quieter and cooler then the 15K drvies, and doesn't require a controller card.

 

[Kadence]

Lorne, I do actually do very major multi-tasking. That's the main reason my computer now usually slows to a crawl (memory is certainly the main bottleneck there, but everything helps).

GarfieldtheCat, thanks for the chart The single-user I/O results were very clear-cut, with the Velociraptor at 70%-100% better over the 15K.5, and even in multi-user it was only 20%-40% worse. The 15K.4 stacked up much better, but not worth the controller cost.

While I'm leaning heavily towards the Velociraptor now, I'd still like to know, if I want a vanilla non-RAID setup, do I really need to spend $200+ on a controller card for an SAS/SCSI drive?

 

[EarthwormJim]

Originally posted by: Kadence
Lorne, I do actually do very major multi-tasking. That's the main reason my computer now usually slows to a crawl (memory is certainly the main bottleneck there, but everything helps).

GarfieldtheCat, thanks for the chart The single-user I/O results were very clear-cut, with the Velociraptor at 70%-100% better over the 15K.5, and even in multi-user it was only 20%-40% worse. The 15K.4 stacked up much better, but not worth the controller cost.

While I'm leaning heavily towards the Velociraptor now, I'd still like to know, if I want a vanilla non-RAID setup, do I really need to spend $200+ on a controller card for an SAS/SCSI drive?

I don't think how you define multi-tasking is how a server defines it. Are you running multiple instances of a Virtual OS? Are you handling requests from thousands of computers for data?

Look we're trying to tell you, SCSI is not worth it for a desktop computer.

 

[Kadence]

Yes and I'm understanding that, as I said I'm leaning heavily towards the Velociraptor. But I'd still like to learn crap Thanks for all the help so far.

And no, that's not the type of multi-tasking I'm doing.

So as I said, if one wanted a vanilla setup without RAID, would they need to spend that much on a controller?

Also, why would one prefer SAS to SCSI or vice-versa?

 

[Nothinman]

I don't think how you define multi-tasking is how a server defines it. Are you running multiple instances of a Virtual OS? Are you handling requests from thousands of computers for data?

Look we're trying to tell you, SCSI is not worth it for a desktop computer.

That kind of distinction isn't black and white. To a disk there is no difference between I/O from mulitple VMs, shared files or multiple userland apps just doing some kind of data processing. If his workload will benefit from lower seek times then it will benefit regardless of whether you consider it a server or desktop setup.

 

[Lorne]

I used to run SCSI alot on my own PC in the past, Its has a whole different level or feeling to it as anyone who has used them also knows what I mean..
Its kind of complicated to describe but the best I can come up with is there is no latency or lag between programs as they load or accesss at once fighting for HD time.
SCSI drives are brutalised as so many accesses at once pound them where as ATA/SATA have to do single funtions at a time and relly on major burstmodes to get each call compleated.

You can get a nice SCSI controller for less then $50 or a SAS controller for less then $150 but then theres drive cost per MB, Also a 10K would be sufficiant as the 15k's give little more performance boost to the higher power consumption and heat they creat, Its up to you if you have the money to blow.
If I could afford it I would deffitnatly jump back on that boat again.

 

[Nothinman]

SCSI drives are brutalised as so many accesses at once pound them where as ATA/SATA have to do single funtions at a time and relly on major burstmodes to get each call compleated.

If you have a SATA controller and drive that does NCQ that's less of an issue although I'm sure the firmware in SCSI/SAS drives is going to be smarter than that in consumer SATA drives.

 

[Kadence]

OK now I'm confused again, though still inclined towards the VRaptor.

Originally posted by: Lorne
If I could afford it I would deffitnatly jump back on that boat again.

Well Lorne you said the Raptor was faster as well as cheaper, now you say you'd jump back on the SCSI boat So is a SCSI faster for a multi-tasker after all?

You can get a nice SCSI controller for less then $50 or a SAS controller for less then $150

If this is the case, then for a vanilla setup, should someone prefer SCSI to SAS so they can get a cheaper controller? Why would anyone want SAS?

 

[MedicBob]

I am switching from SCSI U160 and U320 on desktops to Raptors. SCSI was fun and I still have 2 servers with it. You can get into SCSI cheaper then you might think but it means buying 5+ year equipment. I think for each desktop I had about $200.00 each invested, but only had 36 to 72 gigs of space. I also ran SCSI DVD drives.

Alot depends on what you are really doing with it. IMHO, you should go with a VRaptor. Then build a second cheaper computer and pick up older SCSI stuff if you want to learn it some.

 

[Lorne]

What MedicBob says :thumbsup:

 

[Jen]

scsi for me means realibility , i cant say same for SATA or Raptors . looks over at the raptor that is dead and needs RMA for the past 6 months and i still havent done it . not enough time in a day to do RMAs


Jen

 

[EarthwormJim]

Originally posted by: Jen
scsi for me means realibility , i cant say same for SATA or Raptors . looks over at the raptor that is dead and needs RMA for the past 6 months and i still havent done it . not enough time in a day to do RMAs


Jen

SCSI doesn't really imply reliability. I've had SCSI drives fail on me too. Lost two Cheetahs. I have yet to lose a SATA drive, but I have had two PATA Seagate (7200.7's) drives die on me, and two IBM Deathstars (surprise!).

There's better areas to invest your money in than going with a SCSI setup, the gains are just not worthwhile.

 

[ochadd]

A little late here but...

This is one of those things I think every enthusiast should experience atleast once. A crazy fast storage system gives you system response better than any other upgrade of a modern computer. Throw as many spindles and RPM as you can afford into a system and you will reap the benefits. Stick with RAID 10, RAID 5, or RAID 01 and let yourself sleep well at night. Let it run on a UPS in a fairly cool environment and you can put a smile on every time you get behind the keyboard.

I've worked on virtually every storage technology used in desktops through midrange computers released in the last 15 years and RAID with fast drives is still top.

Solid state flash is not ready for the public regardless of how many companies shove them out the door. Imagine if Western Digital tried releasing the Raptor 36GB this year. It's a joke. If you are going to spend that kind of money you might as well get a couple Hyperdrive4 units or a big commercial RAM drive and get some serious performance for the money.

 

[RebateMonger]

I've had friends who tried SCSI desktops over the years. Each eventually went back to IDE hard drives because they could never afford SCSI drives large enough to meet their expanding storage needs. Sure, the fast drives were nice, but disk space trumps disk speed for most home users. You can't do much work when your hard drive is full.

If you want both fast drive access AND large storage at the lowest possible cost, RAID 0 meets those needs for some applications. If you want these properties with reliability and uptime, then RAID 10 has similar speeds but has redundancy. RAID 0 has the worst reliability of any common drive configuration, so keep ongoing disk image backups and be prepared to use them.

And, no, I'm not pushing the use of RAID 0. Most folks aren't careful enough about backups and the probability of disk (and, thus, array) failure is pretty high.