Adding a RAID card

Jeewhizz · 12th January 2009

Hi Guys,

I've got a server here in the office, that I want to RAID 1.

At the moment, it's got a solitary HD in, and I'm planning on sticking a second one in along with a 3ware RAID card.

If I do this, will I need to wipe the initial HD, or will the RAID card not care, and just build the array based on what's on the initial HD?

Cheers!

danfoster · 12th January 2009

Depending on the RAID card (don't have any experience with 3ware so I can't comment) you may be able to set the RAID up by mirroring the initial drive onto another.

JamieBeeston · 12th January 2009

Depends on the OS, but I wouldn't expect windows to do anything other than BSOD on Inaccessible Boot Device.

You might be a little more lucky on Nix.

J

Jeewhizz · 12th January 2009

It's centos

JamieBeeston · 12th January 2009

Then you may well be in luck, the default kernel is pretty tolerant..

J

othellotech · 12th January 2009

No,
when you create the array, the card will initialise (wipe) the disks for you - most hardware raid cards write in proprietory formats as opposed to s/ware (or fake) raid

PeteK · 12th January 2009

Software raid in Centos just with a second disk do you? Then you won't have to wipe and start again.. Not ideal, but better than nothing perhaps

vaserv · 12th January 2009

Expierence says 3ware write something onto the card which stores information about the array. As such you would have to start again. I would probably guess buying two new disks + RAID card then migration ouver would be easier

Jeewhizz · 12th January 2009

Cheers guys - you've confirmed my suspicions, but couldn't find anything anything on the 3ware site about it...

Software raid is an option, but I have the card here doing nothing...

danfoster · 12th January 2009

just to clarify my post above, and pretty much concur with the other replies, my experience has always been that "true" hardware RAID doesn't allow you to do this as proprietary information about the array is stored on the disks. The onboard motherboard "hardware RAID" that you get on cheaper motherboards will sometimes do this as they're not really doing HW RAID.

It might be easier to set up software RAID.

We would generally take an image of the disk and then put it onto the newly created array (which can be achieved by a variety of methods depending on the particular circumstances)

psi · 13th January 2009

3ware will 'initialise' your old drive, removing your data . I'd suggest getting a couple of new drives hooked up to the RAID card and migrating your data.

CentOS has good support for 3ware cards by default.

Titan_Keith · 13th January 2009

Buy a copy of Acronis Trueimage (it's worth having around anyway), image the system off, construct an array, image back on. You might get lucky, 3Ware drivers are usually built into kernels.

James[UH] · 13th January 2009

Quote:

Originally Posted by Titan_Keith

Buy a copy of Acronis Trueimage (it's worth having around anyway), image the system off, construct an array, image back on. You might get lucky, 3Ware drivers are usually built into kernels.

It wont work, as the 3ware card needs to initialise the disk, causing a wipe of existing data.

Titan_Keith · 13th January 2009

Quote:

Originally Posted by James[UH]

It wont work, as the 3ware card needs to initialise the disk, causing a wipe of existing data.

Yup, which is why I said to take an image of the system off, create the array and restore the image to the array.

James[UH] · 13th January 2009

Quote:

Originally Posted by Titan_Keith

Yup, which is why I said to take an image of the system off, create the array and restore the image to the array.

Ah, of course, my apologies.