HP Proliant Microserver RAID Controller | RAID Functionality

[arc3911]

Hi, I wanted to confirm the functionality / working of the RAID controller on-board the HP Proliant Microserver N40L. I presume the same principle will apply for the same RAID controller on any HP server using the same chipset?

Scenario:

• RAID is turned on within BIOS
• RAID1 Mirror is configured with 2 x HDDs, HDD1 & HDD2
• HDD1 becomes faulty and is replaced.

Questions:

1. How does the RAID controller identify which HDD will take precedence (HDD2), is there the possibility that when the new HDD (HDD1) is inserted that the RAID may rebuilt the mirror, but overwrite the data on HDD2 with the contents of HDD1 (technically overwriting the data)
2. If two disks are removed from the RAID mirror and data on one disk is slightly altered (i.e. corrupted data), however does the RAID controller handle this data, i.e. is there a master disk that takes precedence etc?
3. Is there any way to rebuild the mirror specifying the primary disk?
4. How does the RAID controller work? My understanding is the RAID controller is a component of the BIOS (with a BIOS update comes a RAID firmware update).
5. Does the chipset RAID drives within Windows just assistance with the communications between the OS and RAID controller?
6. Is there the need to use AMD RAID chipset drivers over the standard drivers built into windows? (Windows Server 2012) http://support.amd.com/us/gpudownload/windows/Pages/raid_windows.aspx

A few questions there, but I really wanted to get a better understanding of how this works.

[Jeroen_Kleen]

Hi, Regarding your Questions:
1.
Please understand that this RAID controller in the HP Microserver is complete different and not comperable to any other HP ProLiant RAID controller that we offer. This RAID controllers is 100% leveraged off from the AMDI chipset and is what we would call a Software RAID as it needs an Driver to enable the RAID.
Keep in mind as well that this RAID adapter does not support hot-swap.

2.

So whenever you replace the HD you would have to power-down the HP Micro Server first.  As both drives would be removed after a power-down of the server it would be to me very difficult to believe that the RAID set is different again during a new boot (like you suggested).

3.
To me this condition could only apply if both HD's failed. that would be a very rare condition. If that happens then my suggestion would be to only put the drive into the server where you would like to boot from and then it should boot from that harddrive (if its of course still marked as bootable).

4.
The RAID adapter makes its RAID set during POST and it uses the driver loaded during OS boot for parity calculations etc. and managing the array. We offer the same functionality in our ProLiant servers on the low end servers like ML110/ML150/DL320/DL160 server line.  Meaning there is no dedicated Array chip that controls the entire Array and manages it like with in HP ProLiant SmartArray adapater. However if you load the online RAID utility from AMD then you can still manage this array in a good way including e-mail alerting for possible failed drives.

5. Not understanding this question.

6.

Preferred I always use the latest Vendor drivers as the embedded qualified windows drivers could be outdated and might have been qualified only during initial release of 2012 over a year ago.


I hope this helps you on the way? Cheers, Jeroen (I am an HP Employee)