# Correctly build Raid1 with a PCI controller card & UBUNTU 10.04 desktop

I bought this card from newegg to add a 2-250gb-disks Raid1 to an UBUNTU 10.04 desktop. I then purchased two WD 250gb Blue Scorpio, built the Raid1 set via the controller BIOS as the manual suggest (F4 after Bios Post).

The O.S. is on another drive, directly connected to my mainboard (intel d510Mo).

The problem is that I'm not sure about the status of this raid and I like to understand if everything works as expected before pushing 100 Gb of data into it.

I'm sure the system recognize the controller because I can see it in Disk Utility as a SATA Host Adapter Sil 3114 lead by a sata_sil driver. Disk utility report them as two separate Peripheral drives. I formatted one of them (ext4) so now I see a mounted drive under Places/computer.

However the other drive is still reported as "Unknown 250Gb".

Here is the result of my sudo fdisk -l I've installed dradm and mdadm.

How can I know If my raid is well set?

As you may guess I'm not an expert, so If you have a good howto I could also go there and start from scratch again.

NOTE: I decided to go for a raid PCI controller because my motherboard has only two sata ports and I used one for a 120 Gb HD for the O.S. and one for the Slim CD/DVD-RW. However the card could also be used just to add other 6 HDD ports (2 sata and 2 e-sata) to the system, so if you think It's better to avoid the hardware bios, doing everything via Ubuntu I'll do as you suggest.

-

## migrated from serverfault.comOct 31 '10 at 10:59

This question came from our site for system and network administrators.

I once tried hardware raid using a RAID controller. The ubuntu server recognized only one HD drive on RAID-10. It did not see the four HD drives that I have. So, fdisk -l will show only one HD drive. Is your case similar? –  Khaled Oct 30 '10 at 12:16
As you can see here (dpaste.com/hold/266982), my systems shows 3 drives: sda is the o.s. disk and is not under raid1. sdb and sdc are both part of the raid set. –  microspino Oct 30 '10 at 12:37

It's a fakeRAID card, so the RAID processing is conducted in kernel anyway. If that's the case, why bind your array to a specific controller and not use Linux MD RAID? At worst you'll get exactly the same performance as with fakeRAID.

Using RAID controllers as anything more than a SATA/SAS interface is a good idea only if it has battery backed cache. In most cases Linux MD will be faster and you can just yank the drives, put them in a spare PC and have access to your data in minutes when the controller dies.

-
Sorry to ask more details: do you mean I need to break the hw raid set built by the controller bios and then re-create It via mdadm? –  microspino Oct 30 '10 at 12:45
No, use the controller as just the interface to the disks, build the RAID with mdadm from the start. –  Hubert Kario Oct 30 '10 at 13:14