[mythtv-users] SATA and DMA (SIIG 3112)

[Preston Crow]

On Fri, 2006-03-31 at 15:26 -0600, leland sindt wrote:
>  Two SD and one HD stream is a *lot*  of data, you may be hitting the real limit of the drive system.
> 
> Yes, it is a lot of data... My orig plan was to use a SATA II controller 
> (but didn't know at the it required pci-e at the time) 
> 
> Hmmm... Anybody got numbers/experience with Hardware/Software Raid 0? Did it result in increased bandwidth? 
> (Less likely with software, I know)

I don't think that's the problem.  I think it's the 3112 controller.

# lspci | grep SATA
01:0b.0 RAID bus controller: Silicon Image, Inc. SiI 3112 [SATALink/SATARaid] Serial ATA Controller (rev 02)

The 3112 controller is problematic, at least under Linux.  I'm not sure
what the technical details are; it's either doing something to the PCI
bus or issuing too many interrupts.  Anyway, I found that while hdparm
reported double the performance on my SATA drive compared to my PATA
drive, HDTV recordings on my SATA drive were full of errors, but
recordings on my PATA drive were perfect.

This is true of every kernel I've tried, including the new 2.6.16.

I now record only to the PATA drive.  (And I'm looking for a PCI SATA
controller with something other than the 3112 chip for a good price, as
I don't want to upgrade my motherboard for a while.)