A few questions on RAID 1

First off you will have to have a RAID controler card, or a motherboard that supports onboard RAID.
Promise makes an excellent line of RAID cards.

Yes RAID 1 does reduce performance.

You should never put 2 hard drives on the same channel if they are RAID 1.
If one drive goes down it will bring the other down with it.



When you create a RAID array in the RAID controller BIOS the OS will see it as one drive. In your case 1 (80) Gb drive. You can partition it however you like in windows.

 

Beg to differ with you on this. One can put two drives on the same IDE or SATA channel and run RAID 1 without a problem. One can also put two drives on the same IDE or SATA channel and run RAID 0. Believe Christer is looking to mirror these in a RAID 1 configuration and his friend is safe either way he wants to go - different channels or same channels. Would add he should go CS on drive jumpers.

Interesting sidebar - although I'm not running anything anymore in RAID 0, just saw some rather impressive test results that blew me away - Two drive Raid 0 configuration vs single drive - average speed increase of only 3%.

 

After a catastrophic hard drive failure on a stand alone server I re-thought my RAID configurations.

4 80 gig IBM Deskstars on a Promise TX 2000 2 channel RAID card.
the config was Mirror / Stripe ( 0 + 1 )
The TX 2000 is a 2 channel card so there was a master / slave on each channel.
Well when one of the mirrors failed it brought down everything.

After speaking with Promise numerious times with no success all data was lost.

During the conversation Promise told me for future reference to NEVER put more than one drive per channel.

All of their upper end cards come with master only cables.

 

Scott:

Not trying to start an arguement but think about it.

Under your "advised scenario ", the only RAID cards that could support RAID 0+1 or RAID 5 would be 4 channel cards and all two channel cards would be limited to 2 drives unless you were running "JBOD" (even that would be a no-no according to what you were told). When should we start collecting settlements for all the false advertising going on throughout the industry?

Now, your previous problem requires a brief explanation - in order to set RAID 0+1 on your Promise TX 2000 card, you had to connect the four disks to the two 2 channel controllers. Disks on the same cable (controller) formed each RAID-0 array and the RAID-1 array was formed from these two RAID-0 arrays, giving RAID 0+1. RAID 0+1 is, in essence two RAID 0 (stripes) that have been mirrored (RAID 1).

When you lost one drive on your mirror, you lost both of them on that particular controller because they were actually in a RAID 0 configuration and that still would have happened whether you were on a dual controller card or a quad. Not necessarily a permanent loss but if one drive goes - they are both gone until the bad or failed drive is replaced. Now, if your problem was more than just single hard drive catastrophic failure, what happened is very understandable because of your RAID 0+1 configuration. (Each of the two RAID 0 arrays is identical.) If it was just single drive failure then the drives on the other (non-affected controller) (the other array) would still be totally intact and you could have simply replaced the defective drive and rebuilt your configuration.

I don't run anything with RAID 0 anymore because I see few advantages and lots of dis-advantages - this also then rules out running 0+1. However, I do a lot with RAID 1 configurations and I always try to keep the mirrored drives on the same controller. Not that I've lost a lot of drives, but I've experienced my fair share and I've never, (repeat never) lost both drives in a pure RAID 1 configuration - thats the beauty of it. I also use removable drive bays and keep drives jumpered CS so its pretty quick to repair a mirrored array in the event of catastrophic drive failure.

I think you got a bum steer from whomever you talked to at Promise Tech Support. We call those the NFG's - (New ****ing Guys).