Poor RAID5 with ML115 G1 and Server 2008 x64

[Gary Shelton]

I've got an ML115 G1 we purchased in December as a replacement for our little Exchange server (an ML110G3). It's going to be running Exchange 2007 SP1, and I'd like to run that on Windows Server 2008 x64, if possible. However, I note that the RAID-5 performance is abysmal using the nVidia Mediashield - I get approximately 8-10 MB/sec when either reading or writing. This was verified with MS' JetStress tool. I know that host-based RAID tends to be somewhat slower than a real intelligent RAID controller, but this is ridiculous. The CPU load remains low, so I don't think it's a resource contention issue.
I'm running 4 HP 160GB SATA drives in RAID-5. I've used both the official HP drivers, and the latest ForceWare for nForce 4-series chipsets from nVidia, and in both cases the performance is terrible. The machine is running the current BIOS for G1 servers. Has anyone else noticed poor performance at this level with any other OS? I'm wondering if there is a certain way the array needs to be 'assembled' or something, as this performance seems too poor to just be a badly-written x64 driver.

[AycheKay]

Wondering where your at with this one.

I'm not familiar with the G1 but does it allow you to configure your RAID array entirely in the BIOS, before you install the OS?

We have a G5 with nVidia motherboard RAID and it does allow us to do that. Of course, we do have to press F6 to install a RAID driver during the OS install. I'm still setting it up, not sure what the performance is like yet.

[Gary Shelton]

I spent a significant amount of time testing the G1 and Windows Server 2008 (more than I should have, since this was to be a production server), and determined it wasn't just RAID 5 that had poor performance. The nForce controller under Windows Server 2008 definitely had substandard performance, in any RAID mode, and even in non-RAID mode. Even with a RAID-0 array, the best performance I could get out of the drives was a litle over 11MB/sec sequential read - write and random performance were worse. This 11 MB/sec was pretty consistent, regardless of what mode the controller was used - no RAID, RAID 0, RAID 1, RAID 10, and RAID 5.
The G1 does allow one to configure RAID through the BIOS, and I used the BIOS setup to configure the RAID arrays. I went so far as to download the Vista 64 drivers for the nForce chipset from nVidia directly, but this did nothing to improve the performance.
In the end, I loaded Windows Server 2003 x64, and my performance difficulties went away (with RAID 5, I believe I was getting approximately 120 MB/sec read, and about 50 MB/sec write with 4 drives). This was better performance than my ML350 G5 with an e200 controller manages, so I was pleased.
I worked with HP Support on the issue, and it was determined there was nothing wrong with the hardware, which certainly leads me to believe that the issue had to do with drivers.
Since the G1 and the G5 use the same chipset, I would be greatly surprised if there are performance differences between the models under Windows Server 2008.