SATA mirrror performance

Hi,

I'm not sure if this is the right forum, but since the main keyword is performance, I'd try here first.

I have just installed two 500G SATA discs from Seagate, model ST3500641AS in an ASUS M2N-E motherboard (nVidia MCP55 chipset). Since this is a home desktop and I need dual boot, I used nVidia's RAID technology to create the array, while still using the previous disks for booting.

Well, the suggested device to control these disks, IIRC, is ataraid, so I went for it. But its performance was incredibly slow. I had less than half a megabyte per second in a raw transfer (dd). Formating 100G UFS2 partitions take more than a minute. And all this was drivers fault, as far as I could notice from "systat -v" output. The array was operating near 100% capacity. While running newfs, and this I remember for sure, the array was performing at 4 (four!) transfers per second, and near 100% load.

I also noticed that ataraid does not integrate with GEOM. Shouldn't it be?

Just to be sure it was no defect in disks, they worked perfectly in Windows XP. So my solution was to build a whole disk RAID1 device using gmirror, but now I have two independent and non-interoperational RAID technologies. Indeed, I am very luck that nVidia's RAID does not use the same sector as gmirror for metadata, or if they use, that it does not clash.

After using gmirror, now I have the RAID in its full performance, getting over 60Mbytes per second at raw reads, very near the 70MBps from the specs. Could only be better if we already had NCQ working.

Now the question: Is this expected? Is ataraid somehow deprecated?

If that matters, this has been done on the last week's RELENG_6 source build. The CPU is an AMD Athlon 64 X2 5200+, with 3G RAM.

Jonny

--
João Carlos Mendes Luís - Networking Engineer - jonny@xxxxxxxxxxxx

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