Upgrading RAID Array

[Crispy Beef]

Hi,

I build a Gentoo server for a client a couple of years ago which consisted of 16 SATA drives configured in a RAID array. There are two 3ware cards with 8 drives on each, each of these cards is setup with a RAID 5 array (hardware) and then the two arrays are combined to create one large volume to store data.

A hard disk upgrade is on the cards for the summer with the release of 1TB SATA drives the client wants to up storage space. Basically I wanted to check that I'm doing this the best way, which is; take a full back-up just before the upgrade, switch all the drives, build the new arrays and restore the data.

I assume that's the best (and safest) way to go about this?

Seeing as the RAID arrays are RAID 5 I wouldn't be able to swap out one drive at a time with the drive data being rebuilt as that would result in the larger new drive being downsized to match the rest in the array?

Thanks for any help, I'm still quite new to RAID and this will be my first major upgrade of a system.

Cheers.
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Crispy

[Cyker]

Yup, that is definitely the safest (And, IMHO, best) way.

With software RAID, it *is* possible to replace all the drives one-by-one and then, once they're ALL upgraded, expand the array to use the new size.
Some hardware RAID cards can do a similar trick

With either, it is highly risky and takes phracking ages.

If you have the ability to backup the whole thing somewhere, swapping the drives out, then restoring everything back, I'd highly recommend doing that instead!
It's safer and probably a lot faster too!

[Crispy Beef]

Thought it would be the best way just needed to get a second opinion before I destroy something. Just have to find something to back the lot up on easily, I guess a tape drive would be the easiest...
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Crispy