Date: Mon, 25 Oct 2004 20:06:25 +0200 From: fandino <fandino@ng.fadesa.es> Cc: freebsd-current@freebsd.org Subject: Re: FreeBSD 5.3b7and poor ata performance Message-ID: <417D40A1.9030802@ng.fadesa.es> In-Reply-To: <417D3F12.20302@DeepCore.dk> References: <14479.1098695558@critter.freebsd.dk> <417D25E8.6080804@ng.fadesa.es> <200410251928.01536.victor@alf.dyndns.ws> <200410251837.58257.Thomas.Sparrevohn@btinternet.com> <417D3F12.20302@DeepCore.dk>
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Søren Schmidt wrote: >>> >>> please can you post how do you solved the problem? >> >> >> atacontrol mode <channel> DMA4 DMA4 >> atacontrol mode <channel2> DMA4 DMA4 >> >> The reason is that the motherboard only supports ATA100 on two out of >> four IDE channels and hence you need to force the two other channels >> to run at DMA66 > > > How do you come to that conclusion ? There is no such limitation AFAIK. > > However you can only get a total sum of 133MB/s divided by number of > disks (and minus some overhead on older system there is typically > 110MB/s effective bandwidth).. > > The real explanation is much more likely that the timing specs are > marginal (overclocked ?) for the disks, which causes problems.. no, it is my home PC in which I work so it's important stability (not overclocking) and disk redundancy (vinum, gmirror) Also, there is an unresolvable question. Why two 52MB/s disks in raid0 has a throughput of 40MB/s and for raid1 18MB/s??
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