Date: Mon, 22 Feb 1999 18:36:42 -0500 (EST) From: Andrew Gallatin <gallatin@cs.duke.edu> To: freebsd-scsi@freebsd.org Subject: dual-channel U2W scsi performance Message-ID: <14033.59216.903659.321869@grasshopper.cs.duke.edu>
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I have several servers whose motherboards have on-board dual-channel Ultra2 SCSI controllers such as: ahc0: <Adaptec aic7896/97 Ultra2 SCSI adapter> rev 0x00 int a irq 0 on pci0.14.0 ahc1: <Adaptec aic7896/97 Ultra2 SCSI adapter> rev 0x00 int a irq 0 on pci0.14.1 I understand I should be able to hook older Ultra-Wide devices to each channel. Assuming I do this, and the theoretical max of each channel is reduced to the Ultra-Wide 40MB/sec max, should I be able to come close to getting 80MB/sec out of the adapter when saturating both channels simultaneously? ( Assuming I have a memory system & PCI bus that can handle it, enough drives/buses, using a striped filesystem, etc... ) Essentially, I'm wondering if I need to purchase another 2940UW for each server, or if the above on-board dual-channel controller will really be able to run 2 Ultra-Wide busses close to flat out. Thanks, Drew ------------------------------------------------------------------------------ Andrew Gallatin, Sr Systems Programmer http://www.cs.duke.edu/~gallatin Duke University Email: gallatin@cs.duke.edu Department of Computer Science Phone: (919) 660-6590 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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