Can I run multiple RAID arrays on a single RAID card?

I"m looking to buy a hardware RAID card for my Linux computer which I'm building, and I'm specifically considering this Intel model.

I'm planning on running multiple RAID arrays in my computer: a RAID-0 array for two SSDs and another RAID array for some HDDs. (It might be RAID-5, as I want a good mix on speed, redundancy, and low cost) The card supports more inputs than I need, so I'm not going to be running out of ports.

Are RAID cards generally designed to be able to handle these kind of setups? Do I need to buy another RAID card to run each array separately?

Since I've never done RAID before but have studied it pretty extensively to understand how it works, I'm kind of new to this. Do I configure the RAID setup in BIOS with a card like this? Do I need to install some kind of firmware or driver to get this thing working?

Note: this isn't a shopping list, it's a legitimate question about how RAID cards work.

Naftuli Kay

Posted 2012-02-01T02:05:27.740

Reputation: 8 389

Answers

You can run multiple arrays on the card. Arrays typically configured in BIOS. A driver will likley be required and supplied by Intel

Dave M

Posted 2012-02-01T02:05:27.740

Reputation: 12 811

Cool. How do I configure the arrays? Surely, I won't be messing with them in my OS, right? – Naftuli Kay – 2012-02-01T02:11:18.607

Usually the card will come with instructions. Typically, during bootup, you can press a key combination to enter into the RAID card's configuration screen. Or you do it through tools installed from the manufacturer supplied DVD. – surfasb – 2012-02-01T05:47:46.083

It varries, but with a proper raid solution you can create multiple raid arrays out of distinct groups of disks, or even slice a single group of disks into multiple raid arrays. For example, you can take 3 disks and use part of each for a 3 way raid1, and the rest for a raid5, or take 5 disks and use part of each of them for a raid0 and part for a raid5.

Note that you can save a lot of money by skipping the hardware raid support and just using Linux software raid, which often is much more flexible.

For true hardware raid, you will need an appropriate driver, and usually application software to manage the raid from within the os. They also usually have a bios interface to allow you to configure the array before installing an OS.

The cheaper raid cards are in fact, fake raid, which is to say, just a bog standard AHCI SATA controller with special software/drivers (usually only for Windows) and bios extensions that implement the software raid. Linux will see the hardware for what it is, and see each of the individual disks. A software package called dmraid will recognize the raid metadata on the disks and configure the kernel device-mapper software raid driver to access the array, but this is nowhere near as well supported or reliable as the conventional Linux software raid ( mdadm ).

psusi

Posted 2012-02-01T02:05:27.740

Reputation: 7 195

-3

You can have two volumes on one card but make sure you have enough cable slots (2) for each volume of diff. drives

Avoid software RAID at any cost. This way you will have redundancy and save yourself a lot of time. Software RAID is VERY unstable. Worse than software RAID is "FAKE RAID" - the one incorporated in the motherboard.

guest

Posted 2012-02-01T02:05:27.740

Reputation: 1

This is an opinion of yours, not an established fact. If you wish to comment on another person's answer, please earn enough rep for the comment privilege. – Wes Sayeed – 2016-05-16T22:05:40.690