Justin Piszcz wrote:
Jeff has been working on this chipset/patching/etc:
.. Actually, I'm the one working on that chipset etc.. :)
Looks like there are a couple cards sporting this new chip at the moment
.. There are lots of them out there, including Sonnet, Highpoint, and others.
If one bought enough of these, one could possibly achieve speeds in excess(!) of 1 gigabyte/second with enough drives and SW RAID in Linux. Does anyone have such a card? I would be interested if it could sustain the maximum rate from each disk without any contention.
.. Sure, if the bus and memory are fast enough. You'll hit the Linux/libata transactions/sec limit at some point, but I don't know what that is. Eg. Here's a 4X (I think) card in my PCIe video slot: beefy:~# mdadm --create /dev/md0 --chunk=256 -l 0 --raid-devices=4 /dev/sd[bcde] mdadm: array /dev/md0 started. beefy:~# hdparm -t --direct /dev/sd[bcde] /dev/md0 /dev/sdb: Timing O_DIRECT disk reads: 218 MB in 3.01 seconds = 72.46 MB/sec /dev/sdc: Timing O_DIRECT disk reads: 256 MB in 3.01 seconds = 85.00 MB/sec /dev/sdd: Timing O_DIRECT disk reads: 192 MB in 3.01 seconds = 63.79 MB/sec /dev/sde: Timing O_DIRECT disk reads: 256 MB in 3.01 seconds = 85.07 MB/sec /dev/md0: Timing O_DIRECT disk reads: 768 MB in 3.00 seconds = 255.69 MB/sec Similar results happen without the "--direct" flag as well.
2. How 'experimental' is it?
The 7042 chipset is working rather well right now. Older Marvell chips should still be considered "experimental" for the time being. Cheers -- 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
