Messages in this thread | | | Date | Sun, 25 May 2008 13:47:42 -0400 | From | Mark Lord <> | Subject | Re: Marvell 88SX7042 [4 Port SATA PCI-Express x4] Support/Questions |
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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
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