Transparent IDE Mirroring Hardware

The Fat Guy asks: "I'm having trouble trying to find a device that may not Is there any 'in-line' device out there that can transparently mirror IDE drives? I have a need for a device that will connect to an IDE bus (ATA 100) and will then connect to 2 separate (identical if need be, but ideally allowing different geometries) hard drives and transparently mirror them (RAID 1). I can not install an IDE RAID controller (no PCI slot in the embedded box), and I can't do software RAID (it needs to be OS independent). Ideally, I'd like something that would even work with an external USB or Firewire drive controller. CRU once made something similar to this for older IDE drives, but it appears that they dropped the product and did not update it for the modern drives. Any suggestions? Am I wasting my (and your) time asking this?" It's an interesting idea. Does anyone know of a technical reason why such a device can't be made if it doesn't already exist?

Right down your alley

[jcausey]

This link [arcoide.com] has one that may suit your needs. I bought one (from a different company -- can't remember who) for a client about 8 months ago. It works like a charm, and really fits certain needs.

Trivial question, shouldn't have been posted

[Nonesuch]

This is a trivial question that should never have been posted -- simply opening up a recent issue of Computer Shopper to the latest full-page ad from 'Dirt Cheap Drives' would have found the answer, an Arco product for $199:

http://www.dirtcheapdrives.com/cgi-bin/GProductVie wer.exe?ARDUP5.25 [dirtcheapdrives.com]

The product requires the second drive to be of 'equal or better size' to the first, and works with ATA, IDE, EIDE or U/DMA hard drives.

Similar Question: transparent IDE RAID 0 device?

[Nonesuch]

I have a similar, but slightly different question:

Has anybody run across a device that will transparently make two identical IDE drives appear to the controller as a single drive with twice the capacity ( Either striping/RAID-0 or concatenation)?

I know these exist to make several IDE drives in a RAID configuration appear as a SCSI interface to the host system, but cannot find a device that presents an IDE interface to the host.

Specifically, I'd like to be able to have two 80Gb IDE drives appear as a single 160Gb IDE drive to the host OS, with no appreciable loss in read/write performance.

Yes, I am aware that doing pure striping means that if one drive fails, the data on both drives is lost.

Re:Similar Question: transparent IDE RAID 0 device

[MadCow42]

>> Has anybody run across a device that will transparently make two identical IDE drives appear to the controller as a single drive with twice the capacity ( Either striping/RAID-0 or concatenation)?

What you're asking for is RAID JBOD (Just a Bunch Of Disks). Look for a RAID controller that supports JBOD, as many do these days. I know that most of the Adaptec ones do, but they're usually SCSI based, however I'm sure there's IDE ones too.

MadCow.

Not sure if this helps...

[CaptainTylor]

...but Promise Technology [promise.com] makes a network-attached storage device [promise.com] that uses ATA drives instead of SCSI. They also make an interesting external storage subsystem which uses ATA drives, but is SCSI-attached. I may get one of those myself and fill it full of IBM Deskstar 60GXP goodness.

I know that at least one motherboard manufacturer (Iwill [iwillusa.com]) has onboard ATA RAID on some of its more recent boards (according to Maximum PC magazine [maximumpc.com]'s August 2001 issue, the KK266-R for Athlons with PC100/133 SDRAM, last I heard it was selling for $110). Do not know anything about usability of this device in various operating systems though. You'd think it would be implemented in hardware, so the OS just sees one disk device that represents the mirrorset, but I wouldn't swear to anything...

No, I don't work for Promise or Iwill, or any of their suppliers or business partners.

Years ago....

[jsimon12]

I read about why it really wasn't worthwhile to mirror IDE drives. Bascially the MTBF for IDE's in a system are almost identical, so if one device dies, the other will more then likely die as well. Also, if you have them on one controller (I would figure this embedded device would only have one?) then you would be totally S.O.L. if you lost the master.

Re:Years ago....

[TBone]

1) MTBF almost identical. But not exactly identical. Therefore, one drive will die first, at which time you get yourself to CompUSA or something and get a replacement, because it's a sign that your drive are about to go. Besides, that's dumb math, the MTBF for 2 same-model SCSI drives are identical too, does that mean I shouldn't use my SSI drives as mirrors either?

2) One controller. Yeah, but hey, at least if you drop a controller, your data is still there. Then you drop in a new controller.

Redundancy is expensive - if you can't afford it, then make redundant the most vulnerable link - the data storage. If he wanted mega super redundancy, he'd have two servers in 2 physical locations with two network connections between them using multiple controllers to mirror data across multiple disks on each controller. Is this scenario getting ridiculous enough for home use yet?

Re:Years ago....

[Xenna]

Yeah, well basically the MTBF of me and my twin brother are the same as well, but I think we would make newspaper headlines if we were to die from natural causes at the same instant, don't you?

Some advice: don't go near any casino's with your current statistical insights. You'll lose the shirt off your back ;-)

Regards,
Xenna

Google knows all

[bruckie]

I did a Google search for transparent ide mirroring [google.com], and here are some links from the first page:

• CRU IDE Mirroring [cruinc.com] -- "The MiniRAID is an IDE RAID-1 mirroring "Intermediate Adapter". Once the MiniRAID is installed, it will automatically write all the data to both the "PRIMARY" drive and the "MIRROR" drive at the same time. It is completely transparent and requires no special commands to functions. "
  
• DupliDisk II [positiveesolutions.com] -- "DupliDisk II features include: ... fast RAID mirroring ... plug-and-play installation ... support for IDE, E-IDE and U/DMA drives ... transparent system operation"
  
• RHC-IDE-2R [advantech.com] -- "... the RHC-IDE-2R mirrors data to two hard drives simultaneously ... [and] is Host transparent and OS independent, no device driver is required."
  
• ARAID 99-300 [intreq.com] -- "The ARAID unit with hard drives acts as a single IDE disk. This product has the following benefits: No interface card or driver is required -- the unit simply plugs into the IDE bus chain. ... There is no special management software required"

I'm sure you could find more with a few more minutes of searching. Next time try Google before Asking Slashdot.

Be careful

[xiox]

If there's some sort of power glitch, what happens if the data is inconsistent? You'll probably end up with a completely broken file system.

Consider a simple solution. Add another hard drive and rsync the contents from one to the other every so often. Software raid might be an option, too.