firestorm6 19:47 17 Oct 2008

Tricky one here.I have a dell xps computer.It went wrong and the enginner had to replace the power supply and the motherboard.I did have 2 x 500 gb drives on raid and mirroring each other so if one hard drive failed i would still have the other drive with all my stuff on it.Now it shows both drives but not mirroring each is striping and the other is just there.If i turn on raid for both of the drives i get a boot error message.I have raid on for just one at the moment.The pc is running fine but when i contacted dell they said the only way to get it mirroring again and working correctly is to wipe the drives and start again which defeats the object of it.Is this true or am i missing something.I have built my last 2 computers myself but this is the first time i have had raid.Thanks for any help.

  UncleP 09:46 18 Oct 2008

I have been running a RAID1 array for the system disk on my computer for the last three years. It has failed on two occasions, both of which were due to repairs being carried out (replacing the DVD R/W and, recently, the graphics card and power supply). In both cases the machine continued to re-boot and operate correctly, but showed the array as 'degraded'. This was cured by running the nVRAID manager utility which re-built the array - took a few hours but no data was lost.

I find it difficult to imagine how you managed to arrive at a striped (RAID0) array on a single disk - it's possible, but unlikely to happen without very careful planning. What RAID system are you using, by the way?

You need to use the RAID diagnostic utilities to check on the present status of the array; first, whether the HDs themselves are healthy (otherwise you need to replace the failed disk). If they are ok, and one of them still carries its copy of the original system, it should be possible to re-build the array using the utility provided for that purpose. If the other has been corrupted, it may be wiped clean before re-building the array.

You should be able to inspect the non-system disk (the one 'just there'). It should have an assigned drive letter, and carry the OS and data as it was before the array 'broke'. I assume you have every thing backed up just in case you have to start from scratch again - but, I repeat, this shouldn't be necessary.

  MarvintheAndroid 10:07 18 Oct 2008

Alternatively you take an image of the one working drive, along with creating a boot CD, then reformat the drives, set up raid mirroring, and then recover the image onto the mirrored drives. This may be quicker than re-building the array, and has the advantage that you have a back-up copy if it all goes south.


  firestorm6 15:53 18 Oct 2008

right,both drives are healthy and should be raid 1.I do not have everything backed up as i thought that the whole point of a riad 1 system is that is would mirror itself and back itself up lol.There are 2 drive letters now but one seemilnly will not boot without the other as i have tried disconnecting one at a time and tried to boot that way.If i do on one i get a boot error.On the other i get a red error message saying just error.But if i boot with one on raid and the other just as a drive which says on then the system boots fine.The other thing i could try to delete the one that is stirping but how do create an image of it and how do i do a boot cd?Thanks again/

  MarvintheAndroid 02:11 19 Oct 2008

According to its blurb, Acronic TrueImage supports RAID. Suggest you give that a try.


  UncleP 12:24 21 Oct 2008

Sorry, I've been out of commission over the weekend, only now getting back into working order.

Yes, the RAID manager expects to find two disks, and doesn't like it if there's only one there. It doesn't matter is the array is degraded, it will still boot ok. In addition, I think there are small differences between the mirrored disks and a master (system) disk from a non-RAID configuration, so you can't just use the surviving disk to boot conventionally.

I wouldn't regard a RAID1 array as a complete back-up system in itself. The basic problem is that the two disks are not independent, and may be affected by the same failure mechanism eg getting a malware infection, motherboard blowing up, house burning down - nothing serious, you understand! So its better to have a back-up which is physically separate from the computer and can be moved or stored elsewhere.

I use Acronis TI to store a disk image on an external HD, which I use only for back-up, so it normally not connected and experiences only light use to prolong its reliability and life. But I've never had to use it in an emergency, only to test it to ensure that it works.

No, the main advantage of the RAID1 array is that, if you do have a disk problem, the machine continues to operate normally until you replace the faulty disk or re-build the array. Having said that, the disk imaging system does much the same thing and is a more complete back-up system. But having the re-build utility on the system, it's simpler for me to click on that and start the repair than dig out the components of the back-up system - not quicker, possibly, but simpler, and I'm getting idle in my old age!

You don't need a boot CD if you re-build the array, but I strongly recommend you generate one if you try out the Acronis system (during installation).

  firestorm6 17:24 22 Oct 2008

Thanks for all your help.

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