The Intel Rapid Storage / LSI Megaraid

G

gunz

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Oct 4, 2014
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I am building a server machine at the moment, this is for the first that I build a server machine for production use so I have to get some help. :) I would like to run a Proxmox VE on it but I've got some trobules managing HW Raid to work. The server has special motherboard designed for servers. The model ishttps://www.asus.com/Commercial_Servers_Workstations/Z9PAD8/
It has two types of RAID built in - the LSI Megaraid and Intel Rapid Storage
My first idea was to setup the RAID 1 using one of those systems and than install the Proxmox VE on that RAID partition. But the problem is that when I setup the raid the linux does not recognize it as raid partition and instead it show all the disks separately as /dev/sdX.
I have 4 disks installed on that machine:
2x Intel SSD 240GB - for the first RAID 1
2x WD 2TB - for second RAID 1
I made this stepes: 1. Set the SATA mode to RAID in BIOS
2 Started Intel / LSI utility to setup raid array
3. Started installing proxmox
4. Did not see any of the raid arrays in linux installation
I know that there is a possibility to run a software raid using mdadm instead of hw but I would like to use the hw one.
Is there any way to setup Proxmox on HW Raid using on of those technologies ? Or should I better use software raid ?
Thank you. :)


 
Hi, theses raid controllers are software raid controllers.

What they are doing really, is to write on the first disk block the raid configuration,

then this is the driver in linux guest (if they support it) which tell to mdadm how to build the raid.

(same for windows).

So, anyway, you need to use mdadm with theses controllers.
 
If you read the specs carefully you will notice that it explicitly states "Support Software RAID".

As to your question: IMHO a server motherboard should come with ipmi/kvm and not as is the case with the Asus motherboard as an option with extra cost. Personally I would never buy a server board without ipmi/kvm.

For a decent server motherboard you should look at the offerings from SuperMicro. With SuperMicro you will get a real hardware raid controller from LSI.
 
Hmm but I meant the it would be possible to use this tutorial but for classic proxmox installation. And about MB: I discovered that my MB has the iKVM module built-in but didnt know about it, so one more thing to configure :)
 
A "real" hw RAID Controller costs what? 400 - 500 bucks? I doubt that such a chip is soldered to your mb.

Why are people opposed to mdadm? It's perfectly stable, backwards compatible into the 90's (literally) and first and foremost, it's portable. I somehow believe that's a terminology problem: People think of hard > soft. That's why a hardware RAID has to be better than a software RAID. The truth is, unless you have some crazy array consisting of a mirrored RAID 5, I've never seen hardware RAID outperforming mdadm (if configured properly, stripesize / alignment an so forth) on a modern CPU.

On the other hand, what do you do if the "raid chip" on your mobo dies? Do you think you're able to access the raid, assemble the array, mount it? You can most likely forget it.

If this chip is some sort of instruction set for mdadm, it's possible to have truckloads of luck reassembling the array. But I have never seen such a chip. What I've seen though were half a dozen RAID arrays that were inaccessible after the mobo/the raid chip died.
 
Hello,

Thanks for the replies. We have already decided to use mdadm but the problem is that Proxmox does not officialy support that solution. We have successullly setup the 2x RAID 5 using debian installer and then installed proxmox, seems like everything is working fine.
We had to also change the ext3 filesystem to ext4 because of TRIM support for SSD disks.
 
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