On 29 January 2011 23:57, Roman Mamedov <rm@xxxxxxxxxx> wrote:
> On Sat, 29 Jan 2011 23:44:01 +0000
> Mathias BurÃn <mathias.buren@xxxxxxxxx> wrote:
>
>> Controller device @ pci0000:00/0000:00:16.0/0000:05:00.0 [sata_mv]
>> Â SCSI storage controller: HighPoint Technologies, Inc. RocketRAID
>> 230x 4 Port SATA-II Controller (rev 02)
>> Â Â host6: [Empty]
>> Â Â host7: /dev/sde ATA SAMSUNG HD204UI {SN: S2HGJ1RZ800964 }
>> Â Â host8: /dev/sdf ATA WDC WD20EARS-00M {SN: WD-WCAZA1000331}
>> Â Â host9: /dev/sdg ATA SAMSUNG HD204UI {SN: S2HGJ1RZ800850 }
>
> Does this controller support PCI-E 2.0? I doubt it.
> Does you Atom mainboard support PCI-E 2.0? I highly doubt it.
> And if PCI-E 1.0/1.1 is used, these last 3 drives are limited to 250 MB/sec.
> in total, which in reality will be closer to 200 MB/sec.
>
>> It's all SATA 3Gbs. OK, so from what you're saying I should see
>> significantly better results on a better CPU? The HDDs should be able
>> to push 80MB/s (read or write), and that should yield at least 5*80 =
>> 400MB/s (-1 for parity) on easy (sequential?) reads.
>
> According to the hdparm benchmark, your CPU can not read faster than 640
> MB/sec from _RAM_, and that's just plain easy linear data from a buffer. So it
> is perhaps not promising with regard to whether you will get 400MB/sec reading
> from RAID6 (with all the corresponding overheads) or not.
>
> --
> With respect,
> Roman
>
Ah, right. The Ion platform actually supports PCI-E 2.0, but the
controller I'm using doesn't, according to lspci, if I understand it
correctly. SATA ontroller:
05:00.0 SCSI storage controller: HighPoint Technologies, Inc.
RocketRAID 230x 4 Port SATA-II Controller (rev 02)
Subsystem: Marvell Technology Group Ltd. Device 11ab
[....]
Capabilities: [60] Express (v1) Legacy Endpoint, MSI 00
PCI-Express bridge:
00:18.0 PCI bridge: nVidia Corporation MCP79 PCI Express Bridge (rev
b1) (prog-if 00 [Normal decode])
Control: I/O- Mem- BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B- DisINTx-
[...]
Capabilities: [80] Express (v2) Root Port (Slot+), MSI 00
That might explain why the different stripe caches didn't have any
effect either. Thanks for pointing that out, apparently I didn't think
about it when I purchased the (super cheap) card.
// Mathias
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