Thanks I was just hoping for something like 127MB/s divided by 3 = 42MB/s which is the practical limit of the pci bus assuming each disk gets its equal share. 6MB/s is only 14% of that, so I wonder where the lost bandwidth goes :) The reshape takes only 10-15% cpu or so on my 3ghz cpu so dont think that is the bottleneck. Might be interesting to test a pci network controller at the same time had I installed one before the build, that way i could see if the pci bus really got congested. On Thu, 11 Jun 2009, Robin Hill wrote: > On Thu Jun 11, 2009 at 01:36:59AM +0200, Michael Ole Olsen wrote: > > > the slow disks (them with 85MB/s) in the posting are the one on the pci 4x sata controller > > > > the 32bit pci sata (sata_sil) controller has 3 disks connected > > > > the onboard sata2 6x sata connectors have 6 disks connected > > (p5n32-e sli motherboard), i believe all these are sata2 and not shared with > > an ide controller. > > > > so only the pci controller should have bus limitations, but i wonder why it is > > that slow on reshape compared to build. > > > The build was reading (sequentially) from all drives and writing > (sequentially) only to one, whereas a reshape is reading from and > writing to all the drives (including seeking between reads & writes). > This means it is inevitably a lot slower. In addition, you're now using > 3 rather than 2 drives on the PCI bus, which will increase the > congestion. > > Cheers, > Robin > -- > ___ > ( ' } | Robin Hill <robin@xxxxxxxxxxxxxxx> | > / / ) | Little Jim says .... | > // !! | "He fallen in de water !!" |
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