On Thu, Mar 06, 2008 at 04:08:48PM +0900, Tejun Heo wrote: > Denys Dmytriyenko wrote: > >>> Also, few months ago instead of sata_sil24 I had my drives connected to > >>> sata_mv (Supermicro 8-port) and performance was normal... > >> Everything seems okay. I wonder where the difference is. Does "dd > >> if=/dev/zero of=file oflags=direct bs=1M" make any difference? And can > >> you vacate a raw partition and try it on there? > > > > oflag=direct has no effect - same speed. Tried it on a raw /dev/sda device > > and still no difference. It maybe slighly better, giving me 18 MB/s. > > > > Can it be something with the way SiI 3124 controller is configured in the > > system? > > Hmmm... That's strange you did specify the "bs" parameter, right? It > should essentially give the same performance as "hdparm -t". I wonder > where the difference comes from. Ok, after countless night-hours trying different configurations and peripheral combinations, it seems I can get good write performance (55 MB/s) from SATA card sitting in PCI-X slot, but bad write performance (18 MB/s) when it sits in PCI slot. And it is far from the PCI bandwidth limit. I did some research and found out that apparently it is a known issue of AMD-760 MPX chipset. PCI-X bus is on the AMD-762 north bridge, while PCI bus is on the AMD-768 south bridge, which has a write bandwidth limit of 25 MB/s "bug", acknowledged by AMD. See these discussion threads: http://forums.2cpu.com/showthread.php?s=c8040a4e9c9b6390dd389f1b3cca32de&threadid=31211 http://episteme.arstechnica.com/eve/forums/a/tpc/f/77909774/m/1160910035 http://forums.2cpu.com/showthread.php?s=66da493f719e8e64d15dc974cd567192&threadid=23379 Now, I have 2 options: 1. Keep existing system, but utilize 2 PCI-X slots for SATA controllers. This requires using 8-port adapters, like the one I already have Supermicro Marvell based. The question is - how stable sata_mv these days? It still says HIGHLY EXPERIMENTAL... 2. Replace MoBo+CPU+RAM (at least) and keep using SiI3124 based 4-port SATA adapters, as sata_sil24 is supposedly the most stable solution I can get. I'm leaning towards the second option, but it would cost me more, compared to getting the second Marvell based PCI-X SATA card. Can you please advise? Thanks in advance. Regards, Denys -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
