Duplidisk 3 gives RAID 1, and no drivers

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Manufacturer: ARCO Computer Products, LLC
Price: Around $250
Web Site: WWW.ARCOIDE.COM

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Introduction
Remember modems before "Winmodems", also called "soft modems"? True modems are 100% hardware based devices that needed no drivers to function. The software just talks to them using a standard serial port connection. Any software that can open a serial port can hence communicate with the modem.

Well, that was before Chipzilla and the Vole hijacked hardware design and started putting more and more functions from silicon and into the software side, loading the CPU instead of off-loading work from it. So if you choose a non mainstream (non-Windows or non-Linux) OS, there is one problem that eventually will haunt you: Lack of Drivers for an increasing number of devices.

There was once an Intel white paper dated 1999 that mentioned the CPU performance hit of Winmodems. This benchmark showed at the time an amazing 25% peak CPU usage by using a Winmodem, on a 300MHz Pentium II cpu. Yes, 25% of your CPU used to "run" your modem's data pump by software instead of hardware.

I guess you get my point already: moving hardware functions to software is evil. It limits you -- unless the hardware maker documents the protocols and chipsets involved in painful detail -- to running certain "blessed", or "market-share socially acceptable" operating systems. The right solution, however, is to buy hardware that is as much "standards based" and transparent to the operating system as possible, or put in another way, as "software independent" as possible.

Enter the DupliDisk
This long introduction is necessary, I think, so you can fully appreciate the advantages of the software independent design in cards like the Duplidisk 3.

While lurking on the Solaris x86 mailing list I watched some of the advocates, to use one of my favorite punch lines, "rolling and screaming like stabbed pigs", due to the lack of Solaris x86 drivers for the most popular IDE RAID chipsets, and some whispers of "future support" for solaris x86. Speaking of broken promises, questions about 3ware, and ironically, Promise Technology ide raid cards are common on newsgroups, and the question is always: "when will xyz Co. develop drivers for their nnn IDE raid card so I can use it with my {insert OS name here} operating system?

At that time, I suggested they try the ARCO cards. They were happy to hear about an affordable IDE RAID card that's totally transparent to the software. I was surprised to find they didn't know about Arco: I've been using Duplidisk adapters since around 1999. I've got on my inventory a pair of no-slot Duplidisk 1 adapters, plus one of the "ISA slot" version, and one Duplidisk 2.0 adapter, of the "pci-slot" flavor.

All ARCO Duplidisk RAID solutions are software independent by design, and in my experience all do their job nicely, "faking" a single IDE hard disk to the system board, or hard disk controller, while duplicating data on a pair of identical, or similarly sized, IDE disks. You can use different drives, but then the board switches speed to PIO4 (no UDMA), and you will be limited to the capacity of the smaller drive, which always must be the primary.

In other words: the board works by intercepting the data written to the IDE interface and copying it to the drive pair. In the case of a drive failure, the DupliDisk alerts you via its buzzer, and the system continues working with just one drive, until you can install a replacement disk and re-mirror the data. This menas your data is safe from the "sudden death" syndrome that eventually affects all spinning data storage creatures. On the Duplidisk versions that take a slot (ISA or PCI) it is actually used to draw power from the motherboard, no disk data or communication with the O/S takes place through the slot.

Duplidisk 3 Review
After this experience in the Solaris community, I thought this would be a good opportunity to see "what the ARCO guys have been up to" lately. Hence I'm reviewing here its latest card: the Duplidisk 3, in the "No-Slot" flavor. Like the previous incarnations, it's still a small board the size of a 3 1/2" hard disk.

Looking back, the Duplidisk 1 had one serious shortcoming: it could only use disks up to 30 gigabytes. Early versions had the firmware in a old-style EPROM, so upgrading the firmware wasn't easy: you needed to pull the chip and install a new one (or have access to an uv eraser and eprom burner). The DD version 2 solved the firmware issue by replacing eproms with flash memory, and it lifted the HD size limit to about ~ 120 gigabytes. The DD3 can finally handle any big disk you can find these days, with a limit, at least in theory, around the petabyte range.

One convenient feature that has been recently added in the Duplidisk 3 is what the company calls "EzMirror". In simple words, it allows to setup a pair of disks in a RAID1 configuration without the use of their setup utility. In fact the device can now be connected and a RAID1 pair setup on ANYTHING electronic that uses a IDE interface to connect to a HD. Want RAID for your TIVO?, external USB enclosure? The possibilities are endless: non-x86 computers, embedded devices, headless applications, and the like.

The theory of EzCopy is this: you take the original source drive, connect the Duplidisk no-slot between the disk and the IDE port on your motherboard, or hard disk controller card, connect to the DupliDisk 3 a second drive of the same size to act as the mirror, hit the Duplidisk 3's buzzer button in the right sequence, the source drive is copied onto the mirror, and after that you've got RAID.

Hands on the job
I decided to test the DD3 using Solaris 9 x86, and using EzMirror, not the old approach of running the card's raid-setup utility, to highlight the foolproof, software-less and driver-free operation of the card.

Your DD3 board needs to have firmware version 3.13 or higher in order for Ezcopy to be available. Mine was already at this level so I didn't need to mess with the firmware. But in case yours is not, you can upgraded the card's code effortlessly by downloading and running the firmware update with the card connected to any PC.

The test system was my new Supermicro P4SCA, to which I connected a single Maxtor 40gb UDMA HD, formatted it, and installed Solaris 9 x86. So the test was done on a scenario that most users out there would find familiar: a PC with a single hard disk, and a single HD with an operating system and data already on it.

Installing the thing
Even my computer illiterate aunt could have done it. You get one card and 3 80-wire UDMA ATA cables, two regular HD cables with connectors for two drives, and one cable with a single connector on each end.

I got the single-device cable, the blue connector goes to the motherboard, the other end plugs into the Duplidisk's 40-pin IDE connector labeled "HOST". Then I used the other two HD cables provided and connected the original drive (the one with my Solaris x86 and my data on it), to the "PRIMARY" connector on the DD3 card. Then picked a new 40gb Maxtor drive to act as the mirror and connected it to the "SECONDARY" 40-pin IDE connector on the DD3. Always blue connectors go to the Duplidisk card. Not exactly rocket science, or was it?

I now needed to find the right sequence of button-pressing to get the source drive's data copied to the mirror and to have RAID1 enabled. Since the Ezcopy feature is quite new it wasn't described on the tiny printed manual. The ARCO web site, however, has the docs in PDF format, HERE.

The procedure is quite simple: with all HDDs hooked and everything connected properly, power on the system, and when the device's 3 leds blink red (or orange, I'm daltonic :), press the buzzer button in the DD3 6 times (in 8 seconds), then press the button 4 times (in 6 seconds) to have the copy process start.

My eye-hand coordination must be bad, because I couldn't manage to do it the first time, and had to power cycle the system. On the second attempt, it worked, and the three lower green LEDs started blinking in sequence almost like the Knight Rider's car. The copy process started, and I could hear it.

Exactly 60 minutes later, the card's buzzer beeped and all LEDs were solid green: it meant the copy succeeded, and that raid1 was enabled. I hit the reset button, and watched Solaris x86 boot perfectly, now with the two drives in RAID1 mirrored mode.

Sympathy for the Devil
But what is RAID without a disaster to test it? I shut down the system and let it boot again. This time, in the middle of the Solaris x86 boot process, the evil in me made me pull the power connector from the primary hard disk, "soft killing' the drive the OS was booting from, in a Dr. Kevorkian kind of way. Immediately the buzzer alarm on the DD3 went on and almost killed my ears, while the card's led#1 of three on the DD changed from green to blinking red, or orange, you know.

"One drive is dead, you fool" the Duplidisk was trying to tell me. I understood, so I hit the buzzer button to kill the alarm's high-pitched continuous beep that was killing me. In the meantime I watched the second led (drive #2 status) switch to green, and the Solaris x86 boot process continued unaffected.

That is the point where I or you, had this been a real drive death, should run to the store and get a new hard disk, and repeat the mirroring process, this time copying data from the safe drive to the new one.

Conclusion
This is the way every hardware device should be designed: OS-independent and based on accepted hardware standards - like the IDE bus - rather than relying on drivers and proprietary bits. Sheesh, why can't all hardware makers do it like this? The current "S-ATA RAID" feature of Chipzilla's chipsets, like the one in the P4SCA motherboard I recently reviewed, is of no use for non-Windows users, as the proprietary bits were developed only for Win2k and XP.

Finally, it should be noted that I got a bare "no slot" unit that is actually meant for OEMs to adapt to their hardware designs. Arco sells different flavors of the no-slot unit that add a 5 1/4" or 3 1/2" front bay for safe mounting on your PC case, or another "flexmount" approach which can be put in the back of the PC case. Check the ARCO web page for more information. And see the L'INQs below for a few pics and screenshots I took during the review process.

Beware: keep in mind RAID1 only protects you from hardware failure, not user stupidity or software failure. If a worm, virus or admin decides to format or mess your HD layout, both drives will have the mess mirrored for your safety, too. So RAID1 mirror *and* backup your data.

Arco gives you a five year warranty on the device, couple that with a pair of very quiet Samsung HDs with three year factory warranty, and soon you have no excuse for having your data lost with a HDD failure. µ

L'INQs
My review pics and screenshots
ARCO official product page