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I'm Thinking Of Going ALL SCSI ... Worth the Cost Of Admission?

J

Jimbo

Platinum Member
I'm considering going to an all SCSI setup. Right now I have a couple of Maxtor HDDs (Diamond Max 40s) running off of a Promise 66 card in addition to a SCSI Plextor reader and writer.
This is my personal rig at home.
After I invest about $2,500 in X-15 drives and another SCSI controller (RAID 0) will I even notice ANY speed difference?

Jim
 
Nope, SCSI has a terrible price/performance ratio. Even moderately sized network file servers are better off with 7200rpm ATA/66 drives these days, considering the huge price gap, not to mention the cost of the controller.

Modus
 
I bought all my stuff as used or pulls, so I saved a bundle.
Here is what I got:

Adaptec 39160 with cables $175.00
2 Seagate 3rd gen Cheetahs $125ea at auction.
Sony Spressa 8x4x32 CDrw $99 at auction.
Pioneer 303s slotload DVD $105.00
I took the time to find the deals and although it took me over a month to get it all, I really won on value. $629 and I am all scsi!
I've since added a couple IBM 9.1 gig LVD drives and had to fabricate a bracket to mount all 4 drives, but in my opinion, getting an all scsi system was a great value and can be, if you shop, even consider buying used and be patient. 🙂
 
My network file server has 8 hot plugs scsi @ 18 gig, raid 5 span over 8 drives. I don't think IDE can support 8 drives at once.. That's why SCSI is important.

I also have a 13 drive 36 gig/each network storage device.. ide can't do 13 drives either..
 
Going 'all-SCSI' isn't a great idea .. at least not for the home (power) user. Can get much better bang for ur buck by getting a single, small (9GB), fast (10- or 15Krpm) SCSI beast to run ur OS(es), apps & swap/paging file. Using SCSI HDDs for general/mass storage is a waste of money (things like MP3s, downloads, back-up files, ghost images, jpegs, p0rn, etc.). Can pick up 9GB 10Krpm IBM 36LZX (4.9ms seek) for $229 (Hypermicro). That more than enuf room to run both W98/SE/ME + W2K, all your apps .. & prolly even a distro or two of Linux. I have 3 IDE/ATA drives with my system (WME/W2K dual) boot drive (older, IBM 18LZX).
 
For all of you who say that SCSI is to costly, well, that depends on how much you need the speed.

For some the SCSI solution is a cheap solution, because it enables you to use the disks heavily and still have the CPU power to get the job done, for some tasks the SCSI is the only solution (now, i'm not saying that this guy would need it, but obviously he is not satisfied with his IDE solution.).

And for the original question, yes, the difference IS huge, an even bigger if you are in need of the extra CPU time (IDE RAID is still a software based CPU craving interface).

Patrick Palm

Am speaking for PC Resources

 


<< Nope, SCSI has a terrible price/performance ratio. Even moderately sized network file servers are better off with 7200rpm ATA/66 drives these days, considering the huge price gap, not to mention the cost of the controller. >>



Well, what is a moderately sized network, 50 workstations? Do you honestly believe that a IDE RAID solution would be a good solution in this case?

I would recommend a hardware RAID5 solution for any file server serving more than 10 workstations.

Patrick Palm

Am speaking for PC Resources
 
I'm not sure about this but i think the Abit KT7 may be able to support 8 IDE's. It does have 4 IDE controllers(8 drives), and the raid for the second set of controllers can be disabled seperately from teh controller. Hence the possibility!!!🙂
 
forcesho,

<<My network file server has 8 hot plugs scsi @ 18 gig, raid 5 span over 8 drives. I don't think IDE can support 8 drives at once.. That's why SCSI is important>>

Well, first of all, eight drives is not a small file server. But IDE can actually handle that just fine with the addition of a cheap ATA/100 controller card. And now we have cheap motherboards offering IDE RAID solutions for even more flexibility.

PCResources,

<<For some the SCSI solution is a cheap solution, because it enables you to use the disks heavily and still have the CPU power to get the job done>>

Actually, modern IDE Busmastering DMA controllers bring CPU utilization to levels competitive with SCSI solutions. Anand's tests show that even High End Disk Winmark 99 tests show CPU utlization on a Celeron 500 to be below 5% when the system is properly configured.

<<Well, what is a moderately sized network, 50 workstations? Do you honestly believe that a IDE RAID solution would be a good solution in this case?>>

Absolutely. You know, network file servers do a lot less work than people assume. Most of the data transfered is simple application binaries or database files, and the majority of it gets cached by the local workstation.

Look, there are any number of things you can buy for a computer to make it faster. It's easy to go overboard, but we have to remember that the vast majority of these so-called &quot;high end&quot; parts are prohibitive from a price/performance standpoint and usually not necessary for acceptable performance. SCSI tends to fall in that category.

Modus
 


<< Actually, modern IDE Busmastering DMA controllers bring CPU utilization to levels competitive with SCSI solutions. Anand's tests show that even High End Disk Winmark 99 tests show CPU utlization on a Celeron 500 to be below 5% when the system is properly configured. >>



Ok, so how many IDE disks were used in this RAID setup? And what level was used with the RAID setup? If there was no RAID setup, then CPU utilization would be less than 5%, but then the benchmark would also be worthless if you were to judge a server setup, wouldn't it (IDE RAID is still software based so everything going through that RAID will have to be handled by the CPU)? Not to mention that the High End Disk Winmark 99 i not a very good benchmark when it comes to benchmarking server disk system setups.



<< Absolutely. You know, network file servers do a lot less work than people assume. Most of the data transfered is simple application binaries or database files, and the majority of it gets cached by the local workstation. >>





<< Look, there are any number of things you can buy for a computer to make it faster. It's easy to go overboard, but we have to remember that the vast majority of these so-called &quot;high end&quot; parts are prohibitive from a price/performance standpoint and usually not necessary for acceptable performance. SCSI tends to fall in that category. >>



I have built servers for file server and database systems for more than ten years now, and i have to tell you that i am NOT convinced that the IDE interface is anywhere near the performance of the SCSI. If what you are saying would be true, about the workload of the file-servers, then why the heck would anyone make a file server that uses RAID 5, or RAID 0+1, if the performance is not needed, then RAID 1 would be a better choice.

When it comes to file servers, the disk-subsystem is a good place to spend the extra cash.

Patrick Palm

Am speaking for PC Resources
 
SCSI raid is not for the home user. Is this for your personal computer, where you need a couple X-15's and a Raid controller? That's a little overboard. I thought I was going overboard when I got a 9.1 gig SCSI drive. If you want to dabble in SCSI go the cheap route, get a nice 10K drive like Radboy was mentioning, and put it on an inexpensive Tekram U2W card. Or you can get an Ultra160 card but that's not really necessary.

And who the hell would design a network with IDE disks? It just doesn't happen, not in the business world anyways. IDE may be catching up, but SCSI still offers better reliability, expandability, and speed.
 
ahh good ole modus! he's VERY much for price/performance.. just look at his modem threads!

anyway, my point is this. I WOULD see the difference. why? well considering that I'm on a slower CPU, any CPU hit is noticeable. especially when doing the following:

-Playing DVD's (even with my hardware decoder, I still skip if I surf the net, even though the drive is on it's own IDE channel)
-Burning CDRW's (sure burnproof is nice, but it just slows down the burn process by not burning when there's no buffer)
-loading programs/OS's (of COURSE, SCSI with it's low access time is very good when it comes to .dll files. it has to scan all over the place to get them.)
-video editing (sure I don't do it, but when doing stuff like that, you need FAST transfer rates. SCSI RAID would be the ultimate solution)
-servers (I have experiance with this, when you have a large amount of server usage, this is one place where SCSI shines)

you get the picture? sure you can plug 2 or more IDE RAID devices into your computer, but why? you might also want more network cards on a server. I'd much rather just get 1 SCSI card and 15 drives, then have to buy 4 IDE cards (2 drives per channel, 2 channels per card).

SCSI also has external device support, so you can get an external SCSI burner, and don't have to worry about CPU usage or anything like that (cough USB cough).
 
PCResources,

<<? If there was no RAID setup, then CPU utilization would be less than 5%, but then the benchmark would also be worthless if you were to judge a server setup, wouldn't it (IDE RAID is still software based so everything going through that RAID will have to be handled by the CPU)?>>

Right, but the thing is, you don't even need RAID to have eight IDE devices. Many recent BX boards, for instance, implement an onboard ATA/66 controller to supplement the integrated ATA/33 channels, leaving you with room for eight high performance drives. And remember, not many file servers are going to use that many drives. Most small to moderate network file servers use, at most, two main drives and a backup.

As far as CPU utilization, those benchmarks show that DMA busmastering is extremely effective, in fact, the 4% figure can almost be chalked up to the load induced by the benchmark software itself. And that's on a slow Celeron 500, hardly the ideal processor for a file server.

<<When it comes to file servers, the disk-subsystem is a good place to spend the extra cash.>>

Maybe so, but the best place to spend money is on extra RAM.

<<I have built servers for file server and database systems for more than ten years now, and i have to tell you that i am NOT convinced that the IDE interface is anywhere near the performance of the SCSI.>>

Of course not, no one claimed it was. What IDE does offer is the best performance per dollar, and it's completely adequate for most small to medium network environments. The problem is that most people automatically assume &quot;server = SCSI&quot; without examining the real access pattern that the server will be subjected to. If it's just going to be serving a relatively small customer database along with invoice and shipping information, most of that ends up being cached in the RAM of both the server and the client. Here's another thing to think about:

No one considers IDE too slow for personal use. But let me ask you, how different is accessing some data off a local IDE drive to accessing it off a networked IDE drive? Not much. There are only two possible bottlenecks: the network bandwidth itself (which is the same regardless of SCSI or no SCSI) and the possibility of two clients requesting the same data at the same time. What happens in that case? Well, obviously the drive doesn't lock up and retrieve the same physical data twice. What it does is it retrieves the data the first time and gives it the OS, which passes it along to the first client, and then serves the same data, from memory, to the second client, without really touching the hard disk again.

In other words:

- Both SCSI and IDE file servers will be limitted by the 100Mbit (12.5M/s) network bandwidth.

- Under light to moderate loads, neither SCSI nor IDE will suffer from multiple simulaneous data access, since this will be handled by the OS disk routines and cache memory.

- Since IDE is suitable for personal use, and since it does not suffer over a network any more than SCSI suffers, then IDE is suitable over a network.

<<If what you are saying would be true, about the workload of the file-servers, then why the heck would anyone make a file server that uses RAID 5, or RAID 0+1, if the performance is not needed>>

Why do people buy overpriced Pentium III systems with Rambus memory? Why do they buy expensive rings with diamond instead of cubic zerconium, which has an identical index of refraction and therefore perfectly duplicates the only useful purpose of a diamond -- to sparkle and look pretty? Why do they buy name brand peanut butter when the generic store brand tastes the same? Simple. They assumed the extra cost translated into better product, and they never questioned that assumption.

Soccerman,

<<anyway, my point is this. I WOULD see the difference. why? well considering that I'm on a slower CPU>>

Not really. CPU usage in Anand's High End Disk Winmark tests was only 4% on an IDE Celeron 500. Your computer is not that much slower, if I remember.

Modus
 
&quot;In other words:

- Both SCSI and IDE file servers will be limitted by the 100Mbit (12.5M/s) network bandwidth.&quot;

first of all, there's the issue of Full duplex, second of all, there's the issue of gigabit ethernet (which should be in all new networks backbone cabling at least).

&quot;Not really. CPU usage in Anand's High End Disk Winmark tests was only 4% on an IDE Celeron 500. Your computer is not that much slower, if I remember.&quot;

actually YEAH REALLY. why? like I mentioned in my post, if I were burning, I would notice much less slowdown when doing things such as burning and surfing, or playing a DVD and surfing, because SCSI can do these things, with nearly no CPU utilization. don't ask my WHY my DVD skipped a bit while surfing, it just DID.

I guess part of it's becuase of CPU usage spikes (it was using the hard drive a bit, not much at all).

Finally, considering that the Hard drive is the most used SLOW device on the computer (CDROM's aren't used to load your OS every time you start your computer, neither is your modem, however there ARE exeptions, though very rare), and considering that access time is limited to milliseconds, compared to, say a 1ghz processor, whose clock ticks every nanosecond, and it's Cache latency is measured as well in nanoseconds (not to mention SDRAM), what CAN be done to decrease latency for your HD will improve performance.

can you imagine how fast the computer would be, if your HD was just Nonvolitile RAM running at clockspeeds of over 100mhz? expensive though it may be now, it would be amazingly fast compared to todays computers. Windows would start up in MUCH less time, becuase the CPU isn't left there waiting for each byte of data to come from the hard drive.

remember, there's a BIG difference between Milliseconds and NANOSECONDS. milliseconds deals in thousandths of a second, NANOseconds deals in BILLIONTH'S of a second. therefor decreasing access time by just ONE millisecond, would be equivilent to decreasing access time by 1000 microseconds, or 1 000 000 nanoseconds.

however, becuase HD's haven't kept up with cpu speed, RAM was introduced, to keep the HD from slowing the computer down immensely (imaging running on you HD, with no SDRAM!).

so, the more RAM you have, the less effect of having a faster HD will give you, for MOST USERS. it will REDUCE the effect of upgrading your HD, when the data is in the SDRAM.

on startup, your HD has to fill the SDRAM up. you get immense lag because of it. on running Quake 3, the same thing happens. if it's not already in the RAM, your computer slows down immensely waiting for your ancient drive to give it the info it needs.
 
To answer your question Jimbo...I think it IS worth the extra money to go SCSI. I can't give you the specs as I don't have them anymore, but I did perform an A/B comparison on my own system when I switched over. I went from a ATA66 Promise Controller running IBM 9.1Gig 7200 drives to an Adaptec 2930U2W running IBM 10k lvd drives. My other port is running 50Pin SCSI for the CD-ROM and Burner, Jazz and Zip Drives and life is good. I never wait, can multi-task without waisting cpu cycles and burn cd's in the background...which I could never do with my IDE system. Hope this helps.


I forgot, I didn't really notice a major improvement in speed, other then HD tach and simular tests. Apps did seem to pop open a little faster, but that might be a mental thing.
 


<< Right, but the thing is, you don't even need RAID to have eight IDE devices. Many recent BX boards, for instance, implement an onboard ATA/66 controller to supplement the integrated ATA/33 channels, leaving you with room for eight high performance drives. And remember, not many file servers are going to use that many drives. Most small to moderate network file servers use, at most, two main drives and a backup. >>



So basically, you are recommending a server without fault tolerance, without the speed increase from the SCSI interface and without the higher quality you actually get from a high-end SCSI drive? I don't think any of that is acceptable. If i were to build such a server for any of my customers, they would certainly hang me the day one disk fails.

I have an example for you, i got involved in a new system setup in a local hardware store, they thought my server would be to expensive for them, then i calculated one day worth of lost data, and half a day worth of down-time, and guess what, my server wasn't very expensive anymore.

People who actually need servers (as opposed to peer-to-peer) actually need stability, therefore fault tolerance is a must, if a HDD crashes you cannot afford the downtime, and you cannot afford the lost information.

And getting back to the speed issue, this same hardware store actually got more out of adding another disk to their 5 disk RAID 5 than they did increasing the memory from 512MB to 1GB.



<< - Both SCSI and IDE file servers will be limitted by the 100Mbit (12.5M/s) network bandwidth. >>



Eh, that would be full duplex 1Gb ethernet for any server i build so the SCSI performance would not be limited by anything.



<< - Under light to moderate loads, neither SCSI nor IDE will suffer from multiple simulaneous data access, since this will be handled by the OS disk routines and cache memory. >>



Well, this simply is not true, first of all, i don't know what the 50 supposed users of this server would be doing in your example, but in mine, they would be working, perhaps accessing a Oracle database, maybe through a java interface (this is a real life example), for them the IDE solution would mean a considerable bottle neck, consuming way too much CPU time (fault tolerance is a MUST so this would be a RAID setup), and so again, this would not be acceptable.



<< Why do people buy overpriced Pentium III systems with Rambus memory? Why do they buy expensive rings with diamond instead of cubic zerconium, which has an identical index of refraction and therefore perfectly duplicates the only useful purpose of a diamond -- to sparkle and look pretty? Why do they buy name brand peanut butter when the generic store brand tastes the same? Simple. They assumed the extra cost translated into better product, and they never questioned that assumption. >>



And why on earth would anyone want to buy a Ferrari when the Lada is so cheap?? That angle goes both ways. And the only useful purpose of a diamond is to look pretty, oh, is that why they make diamond drills, because they look prettier??

This is getting silly, why can't you just accept that IDE is not always the best solution, and that for servers, SCSI is a far superior solution.

Patrick Palm

Am speaking for PC Resources
 
To go back to the original question and leaving the IDE/SCSI discussion in servers to the pro's 😉 , I recently switched from a 2 drive RAID 0 setup with IBM Janus 5400rpm drives to a (still, saving up again 😉 )single Quantum Atlas V LVD SCSI setup (leaving out the CD(RW) and DAT drive out of the equation).

Comparing static benchmarks of the 2 setups shows the IDE RAID setup faster in any benchmark in data throughput, however, actually using it is a different story, as the single SCSI drive gives me consistantly better performance. Most system use isnt large burst of data from your drive, but lots of small bits scattered over the drive. The 6 something millisecond access and search times of my SCSI drive compared to the 14 something millisecond of the RAID setup make the act and feel quicker and more responsive. Not to mention that when you have 2 drives in your system and a cd/dvd with a cdrw, in a normal system your 2 harddisk will be on the same channel, preventing your system to access both drives at the same time as they have to wait for each other to be finished with their transaction. In this light, adding extra IDE cards helps a little, but not much, as for optimum performance, you have to give each harddisk and each cd(rw)/dvd its own IDE channel. So with these nice IDE RAID setups, to get the same type of effective performance, compared to what a single SCSI card can do, you do not have 8 IDE channels avaiable, yet effectively only 4. The more drives you add, the more scsi has an advantage.

To conclude, if you have just a single harddisk, save your bucks and get a fast IDE drive. It wont disappoint you. If you have multiple drives, and you can afford the scsi drives, get scsi and you will notice a very real, real world performance increase.
 
I've used both-once you use scuzzi you will never go back to ide.The system
in whole is WAY faster and more responsive.There is no comparison.I have
2 systems,both are identical accept for h.d. and cd rom.

System#1My system:

inwin q500 full tower case
asus cusl2 m.b.
p3 700 overclocked to 1050mhz
mushkin cas2 128mb ram
seagate ultra 160 15,000rpm 18gig h.d.
adaptec 29160 contoller
plextor ultraplexwide 40x cd-rom drive
plextor plexwriter 12/4/32 burner
asus v7700 64meg gts-2 video card
sound blaster live sound card
3com 905b nic
sony e400 19&quot; flat screen monitor
System#2
My system:2

inwin q500 full tower case
asus cusl2 m.b.
p3 700 overclocked to 1050mhz
mushkin cas2 128mb ram
ibm 75gxp
acer 40x cd rom
asus v7700 32meg gts-2 video card
sound blaster live sound card
3com 905b nic
sony 17&quot; monitor


 
Modus, I agree that for the avarge home user, where price/performance is important, IDE is the better solution.

But in a server, SCSI is the way to go.
One reason is that SCSI drives are generally of higher quality, since the manufacturers know that they're gonna be used for servers and high end workstations.
Another reason is hardware RAID, which is a MUST on a fileserver.
Yet another reason is hot plug disks, something I dont believe exist with IDE drives.

I just hope you never end up making decision about someone's server, cause your price/performance philosophy just doesnt hold true when it comes to servers, on servers stability is priority 1 and 2, and performance is 3, after that, we can begin to discuss price.

A question for you, if you were given the assignment to get a fileserver for a 50 workstation company, would you go with, say a Compaq, or would you build one of your own?
 
From my experience, although I haven't tried the U160's yet,
UW Scsi Harddrives have always left me flat.

I went from a Seagate UW 9.1 gig to an el cheapo IBM Deskstar 75gxp 45gigger
and the IBM seems TONS!!!! quicker and way the hell quieter!!
I am using an Ultra 100 controller from
promise.

But, I know what u mean by your machine hiccuping during cdr burns etc.

That's why I use an adaptec 2930 non bootable controller
with a Teac CDRW and CD Rom solution

Best o both worlds man!
 
Coming from an owner of an all SCSI system with a SCSI RAID controller, I would NEVER go back to IDE. Never.

To some people it IS worth it.

Nuff said....
 
Well, my HD array is all SCSI and I sometimes wonder if I didn't make a big mistake. My setup is very similar to Compuwiz's (I have two 9.1GB 1st gen Cheetah U2 drives that I bought new for $125 each on Onsale, I also have one 18.2GB Barracuda that I got new for $150 on Onsale). My total investment is around $525 for the three drives and the Tekram U2 controller. But, they aren't that much faster than my friend's 75GXP. They are WAY hotter, WAY noiser (not counting the fact that I need a fan blowing across each of the Cheetahs), they were much more expensive and I have less storage space and, in return, they are only a little faster. No, I don't think I would recommend it unless the person has a lot of money and needs the speed. If you don't need the speed, you won't really even notice that you have it.
 
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