RAID 1 set up

To secure my data and avoid having to re-install windows in the event of possible disk malfunctions, I'm planning to set up a RAID 1 array (disk mirroring) on my home PC. It consist of a SuperMicro P6DGU motherboard, 120GB Western Digital hard disk, formatted to NTFS, basic disk. The hard disk is connected to an ATA100 RAID control card (which has RAID functionality built into its BIOS) and not directly to the motherboard. I have Windows XP professional + SP1 installed.

Im planning to create a RAID 1 array by just adding the new 120GB Western Digital disk to the existing system.

The instruction manual of the ATA100 RAID card did not cover the following questions, any answers to which I will be grateful for from experts in this newsgroup:-

Should I convert the existing disk to dynamic disk first?
Should I format and partition the new disk before I create the RAID array?
Can I just add the new disk without having to re-install windows?
Does it matter which PCI slot the ATA100 RAID control card is plugged into?
Are there anything else I should be aware off before I start?

Many thanks,

Johannes,
Canterbury, UK.

 

Hi Johannes, and welcome aboard.

Having been through the RAID wars in January, I'll attempt to answer at least some of your questions. I've taken the liberty of numbering them for ease in doing so.

1) I didn't, and Disk Management still shows them as basic disks.

2) No. Part of the array creation involves copying one drive to the other. Once you've created the array, Windows will see it as a single disk, and you can format and partition to your heart's content.

3) Yes. My system was delivered 14 months ago with my two 100 GB WD drives configured in RAID 0. After a massive system crash (entirely my own fault) Christmas night, data was unrecoverable from the drives, so I started from scratch and set up a RAID 1 system. I also installed a third, identical drive, on which I create alternating backups with Drive Image. In the event of failure of one of the drives in the array, it can be used as an interim replacement ... I would just have to rebuild the array, a matter of less than an hour.

In February, each of the two original drives failed, a week apart (a result, I believe, of the Christmas crash). WD replaced each of them, under warranty, and for a few days I was swapping drives in and out, ending up with three drives that had not been in the system when XP Pro was reinstalled in January.

4) Probably not, but you may have to experiment. My gut feeling is that you should try slot 1 first, but I've never had any problems moving cards around, mostly to provide easier access to connectors, etc.

5) You didn't mention whose RAID controller and software you're using. I've heard of problems with Promise RAID cards, but I have a Promise RAID controller on my GigaByte GA-7DXR+ motherboard, and have experienced no problems at all.

My installation required that the RAID drivers be installed before XP was installed, so that the OS could see the additional two RAID/IDE buses on the motherboard. I don't think you'll be faced with that, because you're using an add-on controller, but check your documentation thoroughly, to be sure.

If you want some further reading on the subject, the RAID manual for my motherboard has lots of information that may be useful to you.

Good luck, and be sure to let us know how you make out.

 

But do be aware that the system WILL NOT boot from the mirror drive unless you do some tweaks. Basically, the copy of boot.ini on the mirror will be the same as on the main drive so will be pointing to the wrong place.

You'll have to create an emergency boot floppy for the system and edit boot.ini to point to the ARC of the mirror volume.

It might work to simply add the mirror information to the main boo.ini file and make sure you select that one if you need to boot from the mirror but I'm not positive of that. No reason I can think of that it wouldn't work but I haven't tried it and can't find any good articles descirbing it so just don't know.

I would strongly suggest that after you get your mirror set up and operational that you disable the main drive and make sure you can boot from the mirror.

And you probably ought to read thru Basic Storage Versus Dynamic Storage in Windows XP.

 

Newt, on my computer the system will boot from either drive in the array if there is a problem with the other drive. No emergency boot disk is necessary. I can't speak for a system that is running from a PCI-based controller card, though.

After building my array, I disconnected the drives from the RAID bus, plugged each, in turn, into IDE 1, and checked to see that the system would boot from both ... it did. Then, of course, I had to rebuild the array again.

 

Thanks for your replies

I have now created a RAID1 array and it works fine. I discarded the raid control card I mentioned in my original post because it caused windowsxp to hang on shutdown and installed instead a PCI ATA/133 card from SIIG (www.SIIG.com). Its drivers installs very easily and to set up the array with the card's BIOS is straight forward. So here is what I did about my original questions:-

1) Should I convert the existing disk to dynamic disk first? No I did not. Kept the disk as basic, NTFS.

2) Should I format and partition the new disk before I create the RAID array? No, I did not have to. The raid controller simply makes an exact copy of the source disk.

3) Can I just add the new disk without having to re-install windows? Yes, I simply added another disk of the exact same size. RAID1 can easily be set up on exsiting windows systems.

4) Does it matter which PCI slot the ATA100 RAID control card is plugged into? Apparently not. I tried two different slots and both seems to work equally fine.

5) Are there anything else I should be aware off before I start? Be careful of older cards. They can cause windowsxp to hang.

I tested out the raid setup by unplugging the power cord from the source disk (in order to simulate a disk failure) and rebooted. Windowsxp booted OK from the destination disk. What I havent done yet is unplugging the cord when the system is running. Further tests will be done when I have time.

I did not have to tweak the boot.ini nor create an emergency boot floppy. The very idea behind disk mirroring (RAID1) is that this ought to be unneccessary.

Thanks for your valuable replies to my original post.

Johannes.

 

Johannes - appreciate your posting back detailed results. Should be a big help to folks reading this thread from the archives who want to do the same thing.