Hello,

I have never done RAID before, so I want to ask you guys how to do it.

Assume, I have a RAID controller and four (4) scsi hard drive.

Add the RAID controller into the machine and connect the scsi ribbon to it.

What do you do next to setup RAID 1 or RAID 5?

it depends on if you want raid 1 or 5

5 is good for redundancy.

1 is good for space and speed i believe.

Could you show me how to setup RAID 1 and RAID 5?

It depends on the controller. Most RAID controllers have a BIOS, which you configure the array with.

Hi Asia,

Which RAID controller are you using?

These are some general pointers, but they should apply to most controllers:

Read the documentation if you have it. If not, read further. :D

When you restart the server, carefully watch the boot process before the O/S starts loading. You'll eventually see the name of your controller flash onto the screen, and a message about pressing Alt-X or something like that to enter the RAID setup utility.

Once you're in, with Adaptec controllers you'll probably have to specify the physical devices that you want to use for the RAID, which RAID type you want to use, if you want to add a spare or not, and then to finalize the configuration. Some controllers, such as Mylex, will immediately begin walking you through a question/answer style setup routine. If you're using Compaq controllers, you may have to use a configuration utility on a CD.

If you told us the model of controller, we'd probably be able to help you out more specifically.

Take care,

George

Hello,


I am planning to either use Adaptec ( not sure of the model) or Mylex eXtremeRAID 1100 32MB SCSI RAID.

- Can you setup RAID anytime you want, or do you set it up before installing the OS or after installing the OS?
- During the installing of RD Linux 7.3, do you need to do anything special?

I'm planning to purchase a RAID controller pretty soon just to try out how to setup one.

in the raid bios, their usually fairly self explainatory. If your using your raid as your boot device, then you need to create it before you install the OS. If you have another hard drive your using to boot, you can create the raid at any time.

Assume you have an active hard drive with data on it, and it is about to run out of space.

Can you add more space by adding two more hard drives and do a raid 5? Will it corrupt the data on the active hard drive with data?


Which way is more preferred?
Setup RAID before OS or after OS installation.
If the machine is running on one (1) hard drive, can you do RAID 5 to add more space without corrupting that one hard drive (first hard drive)?

The best thing to do is to set up your RAID from the beginning.

If you wanted to do a RAID mirror later, you can mirror a drive later by installing the card's drivers onto the running system, checking the boot loader (boot.ini or lilo or whatever) that it'll reference the RAID as the boot device correctly. After shutting down, install the RAID card and the second drive. In the RAID's BIOS, tell it the origin drive (you do know their bus IDs, right?) and the destination drive, and tell it to make the mirror. Reboot, and all should be well.

If you don't have a drive duplicator to make quick-n-easy backups, or if the data is irreplaceable, I probably wouldn't recommend that you try adding a mirror down the road. And I wouldn't try to make it into a RAID-5.

Do it from the start, and be glad that you did. :D

George

Setting up hardware RAID usually starts by booting off of a floppy or going into the BIOS if it's integrated, and creating the layout of your array. After you have configured that, the disks are initialized and the array is actually created. After that, the RAID is totally transparent to the OS.

RAID 1 is mirroring. Not good for space, but redundancy.

RAID 5 is striping with distributed parity. A pretty well balance solution for redundancy and good for space.

http://www.raidweb.com/whatis.html

One thing I think that may not have been mentioned. But when you plug all the disks up, to the cable, you will also need to set the SCSI ID's. These ID's start at 0 and if you have 4 drives will be 0,1,2,3.