Basic Raid Question

[moviejunkie]

I have eight 9Gb drives I would like to take 4 of these drives and create one big drive out of these, then I would like to take the other 4 and mirror the other drives, so if one fails I can replace it with out loosing data, is this possible or would it be better to just mirror one drive.

 

[phillid2]

What I would do is create the big drive under RAID 5 and add an online spare. When a disk fails, the spare is activated and the volume is rebuilt. Once you replace the bad drive, you have the spare again. With 8 drives, you can create a 6 drive volume (5*9 = 45GB) with the 7th being an online spare and the eigth sitting on a shelf ready to plug in. Or you can create a 54GB volume with 7 and the 8th is the spare. I do not think you can mirror the drives individually if they are combined in a volume.

 

[moviejunkie]

if I use an online spare, and I have to pull the drive I wont loose data, correct.

 

[phillid2]

If the RAID volume was set up correctly, and a hard disk fails, the RAID controller will activate the spare and rebuild the array. Once rebuilt, you will be back in business and still have a redundant disk should a second disk fail. You can then pull the failed drive and put in the replacement. Depending on your software or hardware, either the replacement becomes the new spare or the controller rebuilds the new disk and restores the spare.