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Rebuilding RAID on different RAID controller

J

jrbryner

[H]ard|Gawd
Joined
Feb 6, 2001
Messages
1,530
I have an onboard RAID controller on my fileserver (an old IWill KK266-R). I have 2 x 120gb Seagates in a mirror config.Recently though, the board has died. I had thought that I could take either of these drives and plug them into a regular IDE port and they would work fine as single drives, with the data still on them. Is that true?

Also, do I have have to have the same motherboard & raid controller to setup the RAID again, or can I get a PCI RAID card (or another motherboard with RAID on it) and setup a new array and still have all my data on the drives?
 
WIth a RAID 1 config you *should* be able to just plug them into regular IDE controllers or another RAID card and be OK since a mirror the drives are considered totally independent and are just copies of one another. To be safe, I'd plug one drive in to see what happens, leaving the alone just in case.
 
^ as pointed out you should be OK

pretty funny though, I lost my first RAID0 array off a KA266 Iwill
mobo took a powder and I declined to buy a new mobo based on its RAID Controller
havent used onboard RAID controllers since
 
Lost my first array off an Iwill VD133. Lost another off a KK266-R.

Decided RAID 0 for an OS on a desktop machine was bullshit, haven't looked back.
 
Great, thanks guys. I'll try plugging in a drive solo into my main desktop and see how it goes. I'm selling off my main rig to get a laptop, so I'll look for a good RAID card to setup a new fileserver I guess.
 
Well, I took one of the drives and put it in my main machine. WinXP recognized it and all the data is there.... phew! That's a load off my shoulders. Now to get the stuff for the server.

I appreciate the help.
 
This is why controller cards will always be a better solution than onboard solutions, unless they have the same chipsets.
 
One more question...

If I use a card, and something by chance happens to the card, can I take out a single drive and connect to a regular IDE like I just did?
 
jrbryner said:
One more question...

If I use a card, and something by chance happens to the card, can I take out a single drive and connect to a regular IDE like I just did?
Click to expand...

Onboard and PCI based solutions are no different, other than the fact that you can't remove the onboard chipset and put it on another machine.

So yes, you can do that. :)
 
Great, thanks. Didn't know if there was a difference between software RAID (what the onboard is? I think) and hardware (something like a 3ware). Good news.
 
well as far as a mirrored array not in the practical application your concerned about
(rescue from a single drive)
but there is a great difference in many but not all the cards over a ROMB
(RAID On Motherboard)
and OS level software RAID is different from ROMB, but your right that ROMB isnt typically a "true" hardware RAID

RAID the Lesser levels next to last chapter in the excellent As the Hard Disc Spins by Dr Michael Schuette of LostCircuits fame

In the true sense of the word, not all RAID levels are really conforming to the original meaning of the acronym. In addition, there is some confusion regarding the boundaries between hardware and software RAID. The issues of RAID caching versus journaling memory and the so-called write hole are even less understood.

Different “Categories” of RAID

In general, one needs to distinguish between three different categories of RAID, namely:

* 1. Standalone RAID solutions for mass storage in the backplane of servers (fiber channel-attached) or Network-Attached Storage (NAS) connected via Firewire or Gigabit Ethernet.
* 2. RAID functionality via separate Host Bus Adapter (HBA) cards using PCI, PCI-X (64bit / 66 MHz) or PCI-Express (3GIO) interface.
* 3. RAID controller integrated on the mainboard level. Often called RAID-lite because of limited functionality, except for dedicated Server boards. RAID on Mainboard (ROMB).

The third implementation, that is RAID-Lite, is currently gaining substantial popularity since almost every better mainboard manufacturer equips their mainboard with an integrated controller of some sort, the main players at this time being Promise, SiliconImage and HighPoint. The same players are represented in a similar fashion in the realm of host bus adapters found on PCI cards, however, in this case, there is additional competition from 3ware, Intel, LSI Logic and Mylex. Mylex, LSI-Logic and Promise, as well as Adaptec also play a major role in the stand-alone scene with one of the former competitors, namely Eurologic having been acquired by Adaptec. Keep in mind that the listing of companies here is a snapshot of February 2004, the industry is changing rapidly and a few months from now there may be very different players in the same scene.

Software vs. Hardware RAID

Software RAID

In general, both Striping and Mirroring, that is Level 0 or Level 1 RAID, respectively, can be achieved in software alone as long as the operating system supports it. This type of RAID is also called zero-channel RAID (because no dedicated hardware channels are involved)

Hardware RAID

Whether any given RAID solution is Hardware or Software often boils down to a matter of semantics. That is, by definition, any dedicated hardware RAID channels will qualify the array as Hardware RAID. However, often enough another distinction is made based on the presence or absence of a dedicated XOR processor. That is, any hardware RAID controller without the additional controller will often be referred to as software RAID, in other words, there is a grayzone. We will cover the significance of the XOR operations a bit later, for now, let’s start with the “lesser” levels of RAID, that is Level 0, 1, 0+1 and JBOD.
Click to expand...

who does the slicing and dicing of the data stream (CPU vs dedicated processos or RAID Engine) and what overhead it imparts and caches it can employ impact overall performance somewhat in the lower levels, most IDE RAID cards (and likely all with just dual channel controller) are effectively the same as ROMB, but cards capable of a higher stripe (channels) can often handle the overhead themselves and not impact the CPU
 
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