parity drive

AMPLIFRIER · Post by **AMPLIFRIER** » Sat Dec 01, 2001 12:51 am

I have a promise raid card....runing raid 0

i want to add parity (a third drive that will regenerate itself to replace one of the 2 hardrives that compose the stripped array, should one of them fail)

how much of a pain in the arse is it?

im imagining it would be relatively easy......plug it in and let it generate.

i guess what im asking for are some guidelines......id like to hear from anyone thats done this b4.

thanks in advance

AMP

Phantom-Vortex · Post by **Phantom-Vortex** » Sat Dec 01, 2001 1:03 am

I have messed with raid 0 before just has long has the 2 drives are exactly the same, the performance is unbeleiveable in strip mode but if you want it for mirroring thats a little different there are 3 stages of raid (i think) its been awhile but its not to hard,Iused the built on mobo raid.

AMPLIFRIER · Post by **AMPLIFRIER** » Sat Dec 01, 2001 1:07 am

i have raid 0 running right now.......i just dont have the parity drive installed

i just wanna know what to expect weh i go to install the 3rd drive........any optimal way to do it?

amp

onetrueday · Post by **onetrueday** » Sat Dec 01, 2001 1:10 am

I dont think you can do what you're trying to do exactly. I"m not an expert on raid, but follow me. If you have 2 40gig hard drives that are in strip mode, you have 80gigs right? So if you want to add that third hard drive to mirror, you'll need a 80 gig drive. That will slow you down, adding the mirror, but only a little bit. Now, if on eo fyour 40gigs fail; I can see how the 80 can jump in auto. You will have a full backup, but will it be able to run in strip mode?

smaier69 · Post by **smaier69** » Sat Dec 01, 2001 5:26 am

i have a question..... what Promise card do you have? if it doesnt support RAID 5 (byte striping w/parity, which will work with a minimum of 3 drives) as a function/level then you are out. i am unfamiliar with RAID 3 personally, but it will also work with 3 drives.

what i am getting at is, does your IDE (i assume) RAID controller support these levels of RAID? if they are not specifically specified as being supported, you wont be able to achieve any level of parity. most of the consumer-grade IDE RAID controllers only support RAID 0, 1, 0+1, and spanning functions. there are high-end commercial-grade IDE RAID controllers that support more RAID levels, but they can be quite pricey (or as i should say were pricey. for all i know there are new Promise cards geared for this sort fo thing.

AMPLIFRIER · Post by **AMPLIFRIER** » Sat Dec 01, 2001 9:48 am

Originally posted by onetrueday
I dont think you can do what you're trying to do exactly. I"m not an expert on raid, but follow me. If you have 2 40gig hard drives that are in strip mode, you have 80gigs right? So if you want to add that third hard drive to mirror, you'll need a 80 gig drive. That will slow you down, adding the mirror, but only a little bit. Now, if on eo fyour 40gigs fail; I can see how the 80 can jump in auto. You will have a full backup, but will it be able to run in strip mode?

i understand you logic OTD but its not like that........if the parity drive is required to replace one of the active drives.......it will only be replacing half of the 80gigs of total data.

and yes this will slow me down a bit....but id rather sacrafice a little speed for the luxry of having the backup drive there so i dont have to reinstall everything over again.

the card is a Promise RAID tx2

but anyhow.....i was RTFM earlier and in the manual it said....."if the soare drive is on the same channel as the drive that fails....there is a possibility the the drive wont be recognized"
They recommend using a single spare only on the tx4 card i have tx2 :-(

maybe ill just do some vloume spanning :-)

thanks for the replies guys

AMP