HD Performance
 

I am running some DL140's with 7200RPM IDE. I am using DRBD to sync the two devices.

I noticed on a fresh install I get about 2.87Mb/s (seems to be common speed) with hdparm -tT /dev/hda. I made some adjustments (-u1 -c3 -m16 -X66) which I can boost it up to around 5-6Mb/s but I can't get much over that. I know the drives are capable of 40-50MB/s. It runs on a Intel ICH5 controller using SATA.

I don't know that drive type, so the following is only generic info...

According to the man page for hdparm, you shouldn't need to use the -X flag since most hard drives default to their fastest transfer mode at power on. However, you haven't used -d 1 to enable dma transfers for the drive. Have you tried that yet?

Yes, I tried -d1 but it says not allowed.
But I think I found the problem, I noticed there is a 'low level' driver for the Intel PIIX Sata under SCSI (even though it is sata which I consider IDE for all intensive purposes).

I am rebuilding kernel now with support for this and see if this fixes my problem, I have a feeling it will help.