Ask Dan: Drives, drives, drives

Publication date: 14 November 2009.
Last modified 03-Dec-2011.

 

When is RAID not RAID?

I'm hoping to avoid cards that use any system similar to Adaptec's "HostRAID" (have had bad experience with them). Are the Highpoint RocketRAID cards, like this one at Aus PC, just another not-really-RAID system like the HostRAID cards?

Jason

Yes, cheap (or cheap-ish) RAID cards these days are all of the "pseudo-hardware", "firmware" or "driver-based" type, where a lot of the work's done in the driver software by the computer's CPU, not by a chip on the card.

Some people have come to derisively call these cards "fakeraid". The term is particularly popular among Linux users, because there are often no drivers for OSes other than Windows that let you use these cards for RAID, or sometimes even for separate drives. "Real RAID" or "hardware RAID" cards, in comparison, have broad cross-platform compatibility, because they handle all of the RAID stuff internally and look to the computer like a simple controller with a single drive plugged into it.

I've come to use the "fakeraid" term myself a bit, but it's not really fair, because driver-based RAID, like software RAID, still is RAID. But without the right driver, these cards will only work as an ordinary non-RAID controller card, if they work at all.

This doesn't mean you're going to face a vast performance penalty if you compare "fakeraid" with real hardware RAID, because today's CPUs are so fast. But it also means that you shouldn't expect much better performance than software RAID would give you.

Software RAID is also less likely to give you another "bad experience", where for instance a RAID array should be rebuildable, or accessible with a controller card replacing one that died, but actually isn't. Software RAID has other limitations, though, like for instance not being able to boot from the RAID array, or from anything BUT the RAID array in case the array has a problem.

The Wikipedia RAID article currently has a good explanation of software, hardware and pseudo-hardware RAID. And here's a big list of different SATA controller chips, which mentions which are real hardware RAID and which are "fakeraid".

 

The saga continues

Can a Gigabyte GA-MA78GPM motherboard support a RAID 5 Configuration?

B

"RAID controllers" on consumer-market motherboards are always "fakeraid", as explained above, and like the very cheapest standalone fakeraid cards, they don't support any of the really useful RAID modes. Usually it's RAID 0, RAID 1, and RAID 0+1 ("nested" RAID, with one RAID 0 stripe-set mirrored onto another via RAID 1). This last one is sometimes called "RAID 10", as is the technically superior version where mirrored RAID 1 drive-pairs have RAID 0 stripes stored across them. And then there's a non-standard form of software RAID that's also called RAID 10. (Yes, it's all a big mess.)

RAID 0, by the way, stripes data across multiple disks with no redundancy at all, and so is not really RAID, because the R in RAID stands for "redundant", in both popular versions of the acronym. If anything is actually "fakeraid", RAID 0 is it.

The GA-MA78GPM-et-cetera motherboard supports those modes, plus end-to-end JBOD ("Just a Bunch Of Disks"), which is of course also not really RAID.

If you want something better, you're going to have to invest in a "proper" RAID card, or use software RAID.

 

I don't know what was wrong with micro ribbon

I wish to replace a 3.5" SATA HDD with a 2.5-inch SSD. Will the SSD require a special cable?

Don

Nope - they just plug right in. Most current Flash SSDs are made in the laptop 2.5-inch size, but that has exactly the same connectors on the back of it as a 3.5-inch SATA drive.

Parallel ATA laptop drives required a pin-adapter to plug into 3.5-inch-drive data and power cables; the smaller laptop connector added four wires to the standard PATA pinout. But SATA uses the same connectors, in the same location, for all drives with a standard size.

(The only SATA devices I know of that don't have the standard connector locations are special miniaturised laptop components, and Western Digital's 10,000RPM "VelociRaptor" drives, which have now been beaten by SSDs as the ultra-fast boot device of choice for the discriminating enthusiast.)

There's one situation in which this can bite you slightly. If you've got an old-model SATA drive, it may have two power connectors on it, one for SATA and one the old-style four-pin "Molex". The drive makers started making those, in the early days of SATA, when they realised that nobody was making PSUs with SATA power plugs on them yet. If it turns out that your PSU is one such, then you'll need a cheap plug adapter to turn a Molex power plug into a SATA power plug.

(There used to only be adapter cables that did this; now you can get little one-piece adapters too.)

If your PSU was made in the last couple of years, though, it ought to have SATA power plugs already.

(I wrote a big piece about some different SSDs almost a year ago now. All of the drives in that comparison have now been superseded by bigger, faster, cheaper, taller and more attractive products.)

 

The joy of Vista, part 231,847

I've tried to solve this problem myself by googling everything I could find and trying anything that looked remotely like it would work. Here is the problem:

I have a slot loading DVD-RW connected to my PC via a laptop to SATA adapter. It's a new PC so I loaded Vista 64, the BIOS sees the drive and Vista loads without issue. Once inside Windows the drive is invisible and doesn't show in Computer or Device Manager. Going into the BIOS shows the drive, I downloaded Driver Detective and after a scan it shows the drive as unplugged. It's not unplugged and works fine, but of course I can't get it to do anything inside Windows.

I went into the registry to remove filters but there weren't any. I went into the BIOS again and changed the drive from Auto to CD-ROM, then booted and Windows started to load drivers for the drive and it was visible everywhere it should be, but on reboot it vanished again.

I found what looked promising on a forum so I soldered pins 45 and 47 together on the adapter, hooked it up and booted. Windows loads driver and the drive is visible again and works fine. On reboot the drive disappears again.

Obviously the drive works fine, the BIOS sees it, I can boot from it. But Vista just doesn't want to know about it.

The PC is a scratchbuilt case built around the components, that's why I'm trying so hard to get this drive to work; there is no room for a standard DVD drive.

Anytime I change something, Vista sees the drive, but once I reboot it doesn't want to know anymore.

I can't get drivers or firmware from Pioneer, the drive in question (DVR KO-6/1) is an OEM drive. I can't believe that there is no way to make the drive and OS work together. I'm willing to have a go at anything, I'll hack whatever I can so long as it doesn't damage my hardware.

I tried the drive in another PC and the same thing happened, BIOS sees it but OS (Vista 32) does not. Can you help or should I just take up knitting?

Things that may be important: Asus P5K-E mobo Intel Q6600 BIOS- AMI, 03/12/08 Drivers: Tried windows and OEM Drivers, Intel, Jmicron, Marvel Have loaded Vista64 five times on SSD and moving-parts drives. Have visited MS for info. Have changed connectors and gone through all the SATA sockets on the mobo. AAAAGh.

Kelly

You've already done pretty much everything I can think of to make the darn thing work - though I'm not hugely knowledgeable about Vista. This seems to be another of those Things That Vista Just Does, Don't You Love It, and if the "filter" trick doesn't fix it, people just seem to be stuck with it.

The possibility does still remain that there is something physically wrong with the drive, though. You might have accidentally static-zapped it while installing it, for instance; that can half-kill hardware and leave people with these sorts of bizarre problems. It's amazing the sort of random problems that a dud PSU can cause, too, but your drive screwed up on another Vista box too, so either that box also has flaky power or that's not the problem.

If you can try it with a Windows XP PC, do; if it screws up there then it's likely a problem with the drive itself, and if it doesn't then it's Vista goblins and you could maybe just install XP on your computer until you feel like tasting the rainbow of Windows 7.

Note that there could also be firmware issues. Laptop drives are meant to work with laptops, and not even all laptops - just the ones that have that model of laptop drive installed as standard equipment. Laptop hardware in general can, for this reason, be expected to be less widely compatible than desktop gear. This isn't good news if there's no way to update the firmware, of course, but at least it's an explanation.

It occurs to me, however, that you may not be quite as stuck with this hardware, to fit into your funny-shaped computer, as you think.

I presume what you've got at the moment is a SATA laptop drive module, that just needs a pin-adapter cable, like this one, to plug it into normal PC hardware.

It's possible that some other SATA laptop drive module will solve the problem, but that way lies madness, especially if you have to pay for the things before you can figure out whether they work or not. Aus PC Market here in Australia have several such drives, but this doesn't mean they'd be happy to keep swapping them for you until one worked.

There are two things you could try that aren't as depressing a prospect, though.

First option: Get a SATA-to-USB adapter - which is a handy thing to have even if it turns out to be useless to you right now - and use that to connect the problematic drive to the computer via USB instead of SATA. AusPC have such adapters.

That second one has an "external SATA" (eSATA) connector on it, but that's compatible with regular SATA. You're not meant to plug bare drives into eSATA connectors, because that standard is of course meant for external devices, but a bare drive will still work fine from eSATA if you've got the right cable.

The first, more complex adapter has a standard SATA connector on it. (Similar products can, of course, also be found very cheaply from umpteen Hong Kong dealers, if you're happy to wait longer for delivery. Aus PC Market are an Australia-and-New-Zealand-only outfit, by the way.)

Second option: Get a "native" USB slimline optical drive that's scout's-honour sworn to work properly with Vista, and use that.

(AusPC have a couple of slimline USB DVD writers, and the second one even says "Supports Vista"! What could POSSIBLY go wrong?

Such a drive will just be a PATA or SATA laptop drive with a USB bridge adapter that works the same as the stand-alone type, but may still be more likely to work, and will probably fit in your case if you remove its outer enclosure.

(Heck, you may be able to bodge it in there even with the outer casing still on it. Obviously, ripping the thing apart will not be good for the warranty.)

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