I have a Poweredge R510 server with a PERC H700 Integrated RAID controller that is exhibiting slower than expected disk speeds (RAID 1 and RAID 10 arrays) and I'm looking at the configuration of the server.

Running the command omreport chassis biossetup on the server shows me the following configuration setting:

  • Embedded SATA Controller : ATA

I can also see that the possible options for this setting are:

  • off | ata | qdma | raid

I've been looking online to find out what this setting means and what the various options refer to but I've been unable to find anything particularly helpful, so I was hoping that somebody here could help to enlighten me.



2 Answers 2


Off - disables the embedded controller. Should be pretty obvious what happens here.
ATA - sets the controller to ATA mode. Basically, sets the controller to act like a regular ATA controller.
QDMA - Queued DMA: sets the controller to support higher transfer rates than PIO. A driver must be installed to use QDMA mode. Using this mode, you'll likely need to inject a driver during your install sequence to recognize any devices connected to the controller.
RAID - sets the controller to RAID mode. Would allow you to setup RAID levels across multiple devices connected to the controller.

Just to clarify if it isn't already clear: These settings will impact the embedded ATA controller (if you have a CD/DVD drive, it's likely connected to the ATA controller). It would not have any impact to the PERC Controller.

So, lets move on and tackle your actual problem: What kind of disk performance are you seeing and what kind of disk performance are you expecting to see? Is it slow on reads/writes/both? What kind of performance testing have you done to confirm the performance? What kind of (and how many) drives are attached? How are the RAID1/10 arrays configured (ie: 2 drives, 4 drives, 8 drives in a RAID10? Is there a battery backed write cache and are you using it?

  • Heh - good answer.
    – mfinni
    Oct 29, 2013 at 15:38
  • 1
    Thanks, that's given me the information that I needed! As for the actual problem that I have I will put that in a different question, as it could be quite long-winded.
    – paulH
    Oct 29, 2013 at 16:04

This server has onboard SATA support, in addition to your PERC RAID card. So, anything that you configure on this will have no effect on your PERC's RAID performance.

You could turn the onboard controller:

  1. Off : This turns it off
  2. ATA : this makes it a simple ATA controller
  3. QDMA : I can't be fussed to dig up all the details on this setting.
  4. RAID : this would be a simple onboard RAID, probably only supporting 0 and 1, but I'd have to read the docs on your systems motherboard to say with authority.

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