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Freeze! This is a RAID!
by Darin Ames
Published: 3/19/99

Since my article addressing the issue of whether to Upgrade or buy a new Mac appeared on this site, I’ve received quite a bit of e-mail. All the messages I got were extremely friendly and some proved to be quite informative, shedding light on certain issues of which I was unaware. I thank everyone for the great response.

Of these messages, the subject most asked about was the RAID I built for my 9600, Swinger. The need for fast SCSI disk performance seems to be a hot topic, whether your Mac is Beige or Blue. Therefore, I have decided to write a review of the RAID I have. While this will not be a comparison piece, pitting several SCSI cards and drives against one another, I hope it will nevertheless be helpful information for all those interested in building their own Ultra2 SCSI RAID. For those in need of a SCSI card shoot-out, you should read Mike’s review elsewhere on this very site, while anyone in need of one of the most comprehensive, step by step guides to building an external RAID should read the RAID tutorial by those fiends at MacGurus.
But HEY, don’t flip that dial just yet! Read on... those other two will still be there when you’re finished here.

Hardware overview:

This might be a good time to point out the difference between Ultra2 or "LVD" drives and other forms of SCSI.
Below is a table that lists various flavors SCSI and their theoretical transfer limits.

SCSI-1 5MB/sec
SCSI-2 10MB/sec
Fast & Wide SCSI 20MB/sec
Ultra Wide SCSI 40MB/sec
Ultra2 SCSI 80MB/sec

[For more info on SCSI - see the FAQ and Links pages-Mike]

Like all SCSI drives, Ultra2 drives require you to set an ID number for the drive by placing jumpers on designated pins or by attaching connectors attached to switches that enable you to select SCSI ID numbers on enclosure backplanes.
Termination of drives conforms to the law of SCSI; the last drive on any chain must be terminated. When installing drives internally in Macs, terminating the last drive is accomplished by enabling termination circuitry on the drive by placing jumpers on the corresponding pins. Ultra2 differs from this, however. Ultra2 drives do not have termination circuitry and thus must be terminated externally. When used in an external enclosure, this is accomplished by placing a U2 LVD compliant terminator to the connector on the rear of the case. When installing a Ultra2 drive inside a Mac, termination must be enabled on the last drive in the chain. Termination must take place by means of a proper terminator attached to a special connector at the end of the SCSI ribbon cable. On a U2 bus, using the wrong cables will result in poor performance or a problematic array. Using the wrong terminators can damage your drives or your SCSI board. This, of course, would be a bad thing.

<pause for a moment of reflection>

Let's continue.

Another difference of Ultra2 is the amount of cable length allowed. The maximum length of internal and external cabling under Ultra Wide is 4.5-feet. This is why Apple blocked off the external port on the ATTO/Apple SCSI card shipped with some older versions of the Beige G3, and why OEM versions of the JackHammer shipped with a piece of tape blocking the external port. Internal cabling was so long, in both cases, that Apple preferred to discourage use of the external port. U2 chains, on the other hand, can be 12 meters, allowing for more flexibility (providing one is conservative regarding unnecessarily long cable runs).
Obviously, the chief discerning quality that makes Ultra2 so attractive is the speed it offers. U2 offers a maximum of 80MB/sec, compared to U/W’s 40MB/sec. The important thing to remember is that these numbers represent theoretical limits. In other words, all optimum variables must be met to achieve ultimate performance. Don’t think that you’ll be getting 80MB/sec by attaching one Ultra2 drive to a U2 card. (Granted, in most cases, installing one Ultra2 Cheetah to one Initio Miles2 card will yield better performance than two U/W drives striped as a RAID with an U/W card.)
To approach the big numbers, you need to build a RAID. It involves a little work, some patience, and a willingness to learn as you go. The result is more than worth it, whether you’re engaged in audio/video production, high end 3-D modeling, or just want to have the fastest Mac on the block. However you choose to look at it, an Ultra2 RAID can yield numbers that make even seasoned Mac veterans envious.
There are several ways to implement a RAID system. The easiest and most common way is to attach two or more drives to an Ultra2 card. This is a single channel RAID; the drives are receiving and sending data over a single SCSI bus. Another method is to use a Dual Channel SCSI card. This is a SCSI card that has two SCSI signal paths on one card. This will increase the bandwidth for data as it allows you to spread drives out evenly between the two buses on the card. While this is a fine solution for Macs with only three PCI slots, it is not the optimum method. The best results will be had from a "true" dual channel RAID. This is accomplished by using two, single channel SCSI cards and spreading the drives out evenly among the two cards. Moreover, in a six slot Mac with PCI slots split into two buses, each having three slots, placing a U2 card on each bus results in two data paths completely independent of one another. This allows for the maximum amount of data transfer. In any dual channel RAID, the importance of perfect symmetry cannot be over-emphasized. In order to ensure the safest, most solid data integrity, you must make each channel identical in terms of the configuration of attached drives. It is possible to build a RAID without adhering to this rule, but doing so increases the chances of possible instability.
As I was committed to doing my precious six slot 9600 justice, I decided to go for only the best, and thus set out on my quest for a full blown, dual channel, Ultra2 RAID. Little did I know that I was about to enter the "bleeding edge" zone.

Ultra2 SCSI card.

When I decided to go with Ultra2 rather than Ultra Wide RAID, Ultra2 cards were only starting to trickle into the channel. The first two to become available were the Adaptec and the ATTO. I did some checking into both and here’s what I came up with.
The ATTO, while posting fairly good numbers, seemed to display a problem booting from attached RAID volumes. This was an immediate turn off, as I certainly wanted to boot from the RAID. As such, The ATTO card was disqualified. The next contestant was Adaptec. This card boasts a unique solution to the dilemma of mixing Ultra2 devices with other flavors of SCSI on the same chain. Normally, when one does this, the entire chain slows down to the speed of the slowest device. It’s like the weak link in the chain analogy. Adaptec purports to get around this with its proprietary "SpeedFlex" technology. What this is supposed to do is detect non-Ultra2 drives and allocate a separate data path to them, thus keeping the Ultra2 path uncontaminated. While this is great in theory, it is very inconsistent in practice. I’ve been told of many instances in which the card reverted to Ultra Wide mode, sometimes even when only Ultra2 drives were attached. Adaptec has released many updates in an effort to resolve this and only now seems to be getting the bugs worked out. It should be noted that according to reliable SCSI card shoot-outs, such as Mike's, the Adaptec remains the slowest of all shipping U2 cards. Also of note is the fact that Apple had the SpeedFlex technology specifically removed from the OEM boards shipping in current Yosemites, even though it might have solved the great dilemma faced by all those trying to attach legacy devices without resorting to sacrificing a precious PCI slot. This is a significant testimony to the instability of SpeedFlex.
I decided to wait for two other vendors to ship their offerings; the Initio MilesU2W and the Hammer Jackhammer U2. Having won the reputation of being the best U/W controller, I was anxious to try a U2 Jackhammer, but as each promised ship date approached, a new one would be announced. Finally, after weeks of this, the company released information that unlike their U/W Jackhammer, the U2 card would ONLY be available when bundled with one of their own, very pricey, RAID systems. This left the Miles2.
Initio entered the Mac market with great success with the Miles U/W card, offering excellent performance at the lowest price, and information from my vendor of choice, MacGurus, led me to believe that the Ultra2 Miles would be every bit as good. As it turns out, I would not be disappointed. The card came in a well-padded box, in an anti-static bag, with software disks for the Mac containing SoftRAID formatting software, Initio's SmartSCSI utility and a well printed, easy to understand manual. (this is clearly a Mac product—there were no windows disks or logo to be seen—nice touch) As we progress, it will become clear that this is the card to have.
Note: Recently, both Adaptec and ATTO have made some improvements to their cards, but neither has yet to surpass the Initio in terms of performance and price.

Drives:

There are many drives available from many vendors. Ultra2 drives are usually a bit more expensive then others but not prohibitively so. While several brands have received favorable reviews, sticking to my plan of using only the best components, I decided to go with Seagate Cheetahs. These drives have won several awards and richly deserve the accolades bestowed upon them. Running at 10,000 RPM and ranging in capacities of 4GB to 36GB, these drives provide the ultimate in disk performance. At the time I was ordering, the 4.5 GB Cheetahs were hard to come by, so I just said screw it and ordered four 9GB’s. They came in rather no frills packaging, but well insulated from shock and included a very informative manual with exceptionally clear charts detailing all jumper settings. Also included were extra jumpers. As is usually the case, the drives were unformatted and set to ID:0. Holding one of these bad boys in your hand feels truly special. You know you are now in the big leagues. They just feel powerful. If I sound whacked, you haven’t held one. If you have, you know what I mean.

Cables and Terminators:

The Miles2 card comes with a terminated Ultra2 internal ribbon cable, which would be fine to use in most any case. I, however, decided to leave nothing to chance and chose to go with Granite Digital cabling. (Besides, a preliminary test showed that one of the Miles cables was in fact hosed.)
These cables are more expensive but they’re the best you can get. Similar to the Cheetahs, when you first see these cables, you realize what you have been missing and what the computer companies have been skimping on. I needed two internal LVD ribbon cables with pigtail LVD terminators for use on drives installed inside Swinger and two more internal ribbon cables, two external LVD cables and two LVD terminators for the external part of the project.
Why so much? Read on, gentle readers.

Break open the spare room, honey. We've got company:

I knew that at best, I’d have room for only two Cheetahs inside Swinger. I would actually have to remove the internal Zip drive from its front bay of my 9600 to make room for one of them. This still left me with two cheetahs and nowhere to put them. Suddenly, inspiration hit me. I remembered perusing the MacGurus website and seeing a page describing their excellent line of Burly enclosures. I ordered a model 5041 external enclosure. This case can house four drives and has the capacity to have two separate buses. This was important to me, as I was sticking to my dual channel plan. I knew that by filling only two drive bays in the 5041, I would be leaving two open, but this gives me a nice warm feeling… Should I add any more U2 drives, I have a place all ready for them. Along with the 5041, I got three front mounting fan bracket kits, and a temperature readout. When people think of building something like this on their own, they seem to put the cosmetic issue on the back burner. Not I. I was determined to have this baby’s appearance be on par with the quality of the components it houses. The 5041 might not be quite as sexy as the Hammer RAID systems, but the difference in price suddenly makes it more exciting than losing the police cruisers chasing you while Jennifer Tilly and Gina Gershon are busy sucking on your ear lobes.

The glue that holds it all together – Formatting Software:

For software, I had a bit of a conundrum on my hands. I had RAID ToolKit, Hard Disk ToolKit 3.0 (with RAID features rolled in) and SoftRAID. For quite a while, RTK was the standard software for RAID solutions. However, FWB had failed to update the product in some time and thus left an opening for other, hungrier vendors to step up with their own products. Even when HDT 3.0 was released, my early tests showed that while it was fine for formatting individual drives, it was actually LESS capable at handling RAID striping than RTK. Unsure of which way to go, I put my faith in Initio and decided to use the software they saw fit to bundle with the Miles2. I went with SoftRAID and never looked back.

SoftRAID's interface is very simple and elegant. In its default settings, you are presented with one main window with two vertical columns. The right column lists all available devices, or Disks (as they are referred to by the application), displaying individual information such as the SCSI Bus on which it resides, the drive ID number, total capacity, etc. The left column is where formatted, ready to use Volumes are displayed. To create a volume, one must first initialize or format the disk, thus placing the superior SoftRAID driver on the drive and preparing it for formatting as a mountable volume. To do this, one has two choices:

  • Choose "New" from the "Volume" menu and then enter in the proper info such as the name, the capacity, HFS+ or Classic and so on.
  • The other (and more convenient) method is to simply click on the Disk listing on the right and drag it to the left column. Upon releasing the mouse button, the New Volume dialogue box appears.

In order to stripe drives for RAID, one need only select two or more drives in the Devices column (clicking on the first and then shift-clicking the subsequent devices) and then drag them to the volume column. It's just that easy, kids.

Ready to swing?

Seeing as half of the installation would be internal and half external, I had to decide how I would divide the drives among the two channels. I decided to have each channel use one internal and one external drive. While this may be a bit more costly, due to the need for more cabling, I felt this would be a better way to "even" out the two Channels. Once again, the key to successful Ultra2 is balance and symmetry. I was determined to adhere to this.

Installation:

CAUTION: as with any installation that requires you to open the chassis of your Mac, do so at your own risk. In many cases, doing so can void your warranty. If you are unfamiliar with the inner layout of your Mac or are not mechanically savvy, there are many options available to have an Apple Authorized repair center do this work for you. As with anything, when in doubt, lay out. I don’t purport myself to be an expert in hardware design or installation. What follows is simply an account of what I did and how I did it. The key is being careful and using common sense. The reward is having a great RAID system that you built with your own, two hands.

First step was to install the two Miles2 cards. I opened up Swinger, silently thanking Apple for the dramatic change in case design from the dark days of opening up my 8100 and 8500 and walking away, hours later, bruised and bleeding. I inserted the cards in slots 1 and 4. As with any PCI card installation, one must use a combination of care and precise force. Line up the pins so that the card is ready to be slipped into place, then apply steady, firm force until you hear/feel a satisfying "ker-chuck" sound. Once both cards were firmly in place, I pressed the CUDA button, just to make sure the logicboard would accept and play nice with these new additions to the family.

The next step was to install the two internal drives. I reassembled Swinger about half way, standing the case upright, leaving the left side panel and the front bezels off, thus giving me access to the drive bays and connection points on the SCSI cards. I removed the faceplates and unscrewed the drive trays and removed them. I then took two drives and placed jumpers on both to provide termination power to the bus. Even though these two drives were going to be on separate buses, I gave them different SCSI ID’s so that I could easily identify each later on. Assigning an ID is done by simply placing a jumper on the proper pins, as described in the manual. If the manual is not handy, Seagate has an extensive graphical library of all its drives on the web, so one can quickly find virtually any information about any Seagate drive. With the drives prepared, I screwed them onto the trays and slid the trays back into Swinger, securing them with the proper screws.
I then took the first of two internal TPO ribbon cables and connected one end to the first Miles2 card and the other end to the first, or top, Cheetah. This end is where you must place the terminator on the very last connector. This is a must, as Ultra2 drives do not provide termination on their own. In order to connect the drive to the card, I snaked the cable through the small rectangular slot in the metal plate that extends across the middle of the case. I then simply repeated this procedure for the second drive and card.
Finally, I attached the power supply connectors to the drives. (Most Macs will have extra power cables running out of the power supply) I still did not replace the side panel, and front bezels, as I wanted to make sure all was working before I closed things up.

Test Number One.

Before moving on, I wanted to be sure that the two drives installed were in good working order. Making sure all connections to Swinger were in place, I booted and launched SoftRAID 2.1.5. I then formatted each drive. At this point I had two, 9GB volumes. I restarted and made sure that each drive mounted and ran properly. I then installed a System Folder on each drive and booted from each. Once this worked, I reformatted BOTH drives and striped the two together as one 18GB array. I repeated the previous steps to the point where I could boot from this large, striped volume.
While this may seem to be the long way around, it is a good way to gradually ease into the final RAID. By progressing in this fashion, it is far easier to identify and resolve any conflicts or problems, should any arise.

Test Two:

I was now ready to tackle the external half of the RAID. This being my first venture into this area, I must confess that I cheated a bit and had the selfless, monk-like hardware Swamis at MacGurus assemble the 5041 enclosure for me, with all cabling and fans ready for drives to be installed. While it is not that difficult to do this, I wanted things up and running fast. One of my mottoes is "Instant gratification takes too long." You get the point. I prepared the two Cheetahs similarly to the way I had done before, with the addition of attaching side mounting brackets to secure the drives in the case. I then made the proper connections for power, ID selector switches, power-light indicators and SCSI connection. Keep in mind that each drive was placed on its own SCSI bus, necessitating two SCSI ribbon cables. Unlike the ribbon cables used inside Swinger, the termination for these drives would be placed on the external connectors on the rear of the chassis, much like other external SCSI drives. With all connections made, I then attached both the external LVD terminators to each of the two separate buses and attached the two external cables leading from the case to the two Miles2 cards.
I repeated the formatting steps I performed with the first two drives to make sure that all four drives were working well. Finally, I reinitialized the four drives and began to make striped partitions from the four Cheetahs. I did this because I am a firm believer in partitioning large volumes into smaller ones targeted for specific uses. For example, I created one striped volume to hold my System Folder and act as my boot volume. Another volume would hold applications, while another would be a dedicated PhotoShop scratch partition. You get the idea.
With everything running and all cases closed, I began the process of making these new speedy volumes feel like home. I installed Mac OS 8.5.1 on the volume I chose as my boot volume and reinstalled my applications onto another volume and so on. Frankly, the hardest part was deciding on what to name each one. Keeping with a "Vegas" and "Rat Pack" theme, I had to scour my lexicon of Sinatra-isms and such until I came up with a list that appealed to my own warped sensibility. (If you’re curious to know what names I used, visit my site, www.crooner.com, and listen to some sound clips from my CD. If you still want to know, e-mail me and I’ll tell you)

Please put your seat in its full, upright position and fasten your seat belts. The Captain has lit the smokin’ sign, Baby.

Now it was time to give the RAID a run and feel the difference. While I could rush to give you MacBench scores, I’ll first describe the "feel" of the speed boost.
Windows snapped to the screen and displayed their contents instantaneously. Launching applications was faster to the degree where I had the feeling that the app had launched, done the work I intended to do, saved the file in the proper format and then quit a second before I finished the second click on its icon.
Okay, okay… I’m exaggerating a little, but believe me; things were faster than I had anticipated.

Building this RAID took some time and most definately required some patience. Rushing through something as intricate as this will only hurt you in the end. All things considered, however, the overall process was straight forward and conformed to sensible logic. At no point did I hit a road block and scratch my head, trying to think of some radically unorthodox way to accomplish some step in the RAID's completion.

Hardware Review:

The Initio card is a wonderful piece of engineering that provides the best performance available for a U2 card at a price lower than its competitors. Moreover, Initio support is extremely helpful and courteous. Since installing the RAID, I made the age old mistake of fastening an external connecter screw-post too tightly, snapping the female receptacle on the Miles2. Initio sent out a replacement immediately and told me to test the new card before sending the old one back. While they did take a credit card number for security, no charge ever appeared on my statement.

The Seagate Cheetahs really need no further praise. Nevertheless, I would be remiss without once again reiterating just how good these drives are. Yes, there are drives available for lower cost. Yes, some other vendor's drives are of fine quality. Still, when the day is through, Cheetahs set a standard for performance that puts them on a level that far surpasses all other offerings.

The Granite Digital cables and terminators, once in hand and in action, need no help in justifying their cost. Once you've used these products, you will not be able to keep from shaking your head upon seeing the usual, flimsy grey ribbon cables and off the shelf terminators that so commonly come with our Macs and line the aisles of CompUSA

Finally, SoftRAID 2.1.5 has proven to be the fastest, easiest to use drive formatting software one can get. Obviously attuned to what makes for superior performance, the engineers at SoftRAID have developed drivers that are completely 8.5.1 compatible and simply the fastest one can get. Their customer service shines as well. When I was first assembling my RAID, the latest version was 2.1. At first I ran into a couple of problems regarding the stability of the array. This was due to the fact that at the time, Ultra2 was still only just hitting the streets, let alone being implemented in a full, dual-channel RAID. When I brought my problems to Mark James' (SoftRAID's president) attention, update 2.1.5 was issued within days. This update instantly solve the conflicts I was seeing. That, Gentle Readers, is what you call service.

I could go on and on lavishing praise on the individual components and overall power of my RAID, but I'll stop teasing and get to what I imagine most of you are waiting for, test scores. But, before I do, I must discuss something very important to me that should be of equal importance to anyone purchasing quality gear for their Mac. Bear with me.

What you buy and Where you buy it.

We are entering a strange new age in commerce. While the WWW has allowed us, the consumers, wonderful opportunities to comparison shop and find items that otherwise could not be located, it has also afforded many individuals and companies new and exciting ways and means by which to take advantage of us. I shall not single out anyone in particular, but it must be said that some vendors will insist on offering the lowest price for a given item, even if that difference amounts to pennies, at the sacrifice of something that really has no price (yet): Service. Not enough can be said of good customer service, be it pre or post sale. Whether it be for something as simple to operate as a whisk or as intricate as the RAID described above, the guidance and assistance we frequently need from our vendors is really something that cannot be given a price. (YET)
As we see the world of e-commerce expand on a daily exponential rate, I believe we will soon see the birth of a new product: Service. In the fight to boast the lowest price, many vendors leave us high and dry after an item has shipped. This is where I see new firms appearing that, for a fee, will take on the role of the service provider. While this would solve the issue of assistance with product use and maintenance, it will inevitably negate any savings had by making a purchase at a rock bottom dealer. I have always adhered to the idea of "Never be afraid to pay a little more for the best" and it has stood me well. I make no secret that I bought all the components for my RAID from MacGurus. While their prices were among the lowest anywhere, if not THE lowest on some items, the level of support I have always received from them is priceless.
We are entering a new age in commerce and while the future brings with it many great new opportunities, it would be foolish to blindly rush forward without remembering to take along certain tried and true conventions that stand outside timeliness and technologies.
Okay. Off the soapbox and...

Onto the scores.

MacBench 5

As you can see, the RAID slightly out performs the stock IBM drive that came with Swinger. While test scores are great for that "Leo DeCaprio, ‘King of the World" boasting, the real value of a high performance disk system proves itself to you on a daily basis by making your work and play more efficient, powerful and frankly… fun.

Thanks for reading.

Darin Ames
3/99


Related Links:

  • See the site's SCSI/IDE Features page for other RAID/SCSI/IDE/Storage related articles
  • To learn more about SCSI, see the SCSI/IDE topic area of the FAQ and Links (Gen/SCSI area) pages.


Please note that this review, as well as other articles I have written, will be maintained at my site on the "Geek" pages.
darinames@crooner.com
www.crooner.com