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Attaching IDE Disks to SCSI Controllers?
A not-so Anonymous Coward brings this query to the forefront: "A German company has an adaptor that will allow you to use cheaper IDE drives with SCSI controllers. There is also another company selling RAID enclosures that look LVD but take IDE disks internally. Raptor RAID is the name, but I can't find the actual company's web page. I did find This review. Anyway, how do these things work, and does anyone make adapters so an individual can attach an 80gig IDE disk to their LVD chain and save $500+USD per disk."
Then you ask us if you know of a way to convert IDE hard drives to SCSI.
Is this some sort of trick question? If we lose, do we get thrown off the bridge?
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Forget Napster. Why not really break the law?
"Remember when the U.S. had a drug problem, and then we declared a War On Drugs, and now you can't buy drugs anymore?"
Also, there's KT-7 RAID MB which supports ATA-100 and Athlons. In that, you can set up mirrors or stripes as you want. Buy a couple of identical HD's and you're set.
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That said, the software RAID options within linux are still valid, and if you're mirroring, the performance impact shouldn't be much (indeed, reads should be faster if using round-robin).
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Absolutely. I don't mean to say that there is anything wrong with IDE...I have a SCSI controller sitting around in my compuer room because I have nothing to plug into it - all my drives are IDE. However, the guy would be better off spending the money to get a native IDE controller rather than spending monty on hacks to make his IDE drives work on his SCSI controller.
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You want to use a moped to pull an RV. Use the correct tool for the job.
IDE is an end-user driven and targeted technology. It's cheap, as you see in the proce difference between IDE and SCSI drives. However it's also cheap. The protocol is not as robust, or expandable, or bulletproof. IDE is meant for home users who need lots of space but aren't as concerned about reliability.
SCSI is a business, server-targeted technology. It's a stronger, faster, more expandable technology. It's meant for stacking ridiculous abouts of space into small areas. It's intended for corporate applications where you need wide data paths to move lots of data very quickly, or need redundant pathing, or lots of other motivations that 99% of your home users don't need. Regardless of how much data you THINK you move, you have not moved data until you start running systems that load 2G datafiles into a Data Warehouse multiple times a day.
Get an IDE controller that supports the 3rd/4th channel, and quit screwing around with silly adaptors that are a hack to a problem that's trivial to fix if you use the right tools.
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Yes, I just bought a KT-7 RAID. Too bad it doesn't have drivers for Linux. When the BIOS is set to stripe the disks, Linux only sees one of the drives (that is, I've got 2 45GB hard drives, and I only have 45 GB available--with RAID 0 (striping), the two drives *should* appear as one drive, but be twice as big).
Sorry, but the KT-7 RAID won't work if you're looking to RAID your drives under Linux. That is, until Highpoint releases Linux drivers for their RAID chipset.
--Be human.
--Be human.
Linux IDE Raid
I actually corresponded with the guy somewhat, he's very scientific, knowledgable, and motivated to make it work (its his job) so his results are credible.
I followed the pattern and now have a tower with 2 IDE channels on the mobo, 2 promise cards, and two cards with CMD IDE chips in them. I have a couple of CD drives as hda and hdb, then 9 81GB Maxtor drives, each one as the master disk on a primary or secondary interface.
Then I used software RAID 5 on Linux-2.4, and believe it or not (I haven't run the tests in a while, but they were rigorous), I can nearly saturate my 100baseT network with data while reading, or store data quickly enough to keep up with the network. Formatted with ext2, this is a 614GB array.
It looks like the page has been updated recently though, as the I75Raid machine he was working on (>1TB) now has screaming performance, where he was having some problems before.
Other than hot-swappable hard drives, there's simply no reason to pay for SCSI any more, that I can see. This guys performance looks like it stand up to a 1000baseT network and not suffer too badly.
Be aware that an IDE drive with a SCSI bridge board is unlikely to be as fast or reliable as a native SCSI drive. SCSI and IDE drives are designed with different goals.
Mea navis aericumbens anguillis abundat
I've actually heard, from an Adaptec technical rep, who would by definition have an interest in seeing you buy SCSI, so take it how you will, that the only major difference with IDE and SCSI is that the SCSI drives did better in QA and had a higher MTBF, so they got SCSI connectors and boards, and the not-as-good drives got IDE connectors and boards. Again, Adaptec rep.
I do however remember similar stories about Western Digital when their drives REALLY sucked (I've still never ever used one in my machines), back when 540MB was good and 2GB was HUGE, that the drives that went through QA were "Caviar"s and the drives that just got dumped off the line into boxes were their regular model.
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Now I'm looking vaguely at expanding my MP3 jukebox/server to add DivX ;-) capabilities. To do so is economical (100 movies or 400 episodes of Anime per 50gig IDE drive), but only really using IDE equipment. I'd love to find a Linux compatable solution, either software (which I'm vaguely aware exists) or hardware (PCI Card or somesuch).
Any good pointers to... ahem... recent information? It seems most HOWTOs start out warning you that you will have to upgrade to that newfangled 2.2 kernel. Since I'm already happily using 2.4 on ReiserFS, I'd be interested in a modern, inexpensive (this ain't a mission critical server) solution.
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Evan
"$30 for the One True Ring. $10 each additional ring!" -- JRR "Bob" Tolkien
Why bother with a shim when you can get an Adaptec UDMA/66 RAID (AAA-UDMA) card or a Promise SuperTrak 100 RAID card and handle the storage natively? Both products have been available for a little while and are past version 1 drivers, so they should be fairly stable. Both products will do RAID 5 with 8 or so drives (4 controllers, 2 drives each). At 8 80GB drives in a RAID 5 configuration with one hot-spare, you wind up with 480G of safe storage. Put two cards in a system and you're almost at the terabyte mark. I've used many Promise FastTrak cards in small servers to mirror the data drives, and I've never had one card fail yet. (I did have a drive go bad and the product worked as advertised...) I wouldn't bother with a SCSI solution unless you're going with SCSI drives. As usual, use the right technology for the job.
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Raidweb, another IDE->SCSI RAID:
www.raidweb.com
[insert standard IDE disclamer]
It seems that almost all of the IDE based RAID products out there use the controllers from Accusys. Here's one of their products:
8 drive controller
Tried the older, 6 driver version, and it worked pretty well, did about 40MB/sec sustained with 6 drives. Very sensitive to termination.