Date: Fri, 18 Aug 2000 23:23:22 +0200 (CEST) From: Soren Schmidt <sos@freebsd.dk> To: parag@cgt.com (Parag Patel) Cc: robert@kudra.com (Robert Sexton), jonathan.laventhol@imagination.co.uk (Jonathan Laventhol), freebsd-hackers@FreeBSD.ORG Subject: Re: Cheap 1000Gbyte machine Message-ID: <200008182123.XAA80962@freebsd.dk> In-Reply-To: <3689.966632697@pinhead.parag.codegen.com> from Parag Patel at "Aug 18, 2000 02:04:57 pm"
next in thread | previous in thread | raw e-mail | index | archive | help
It seems Parag Patel wrote: > On Fri, 18 Aug 2000 15:57:48 EDT, Robert Sexton wrote: > > > >Can IDE drives release the bus during seeks? Historically thats been > >the big advantage of SCSI: Two IDE drives are no faster than one IDE > >drive, while SCSI scales in performance. > > How about a single IDE (master) drive per controller, that is, no slave > drives at all? This would halve the number of available drives per card > (or require twice the number of cards) but essentially would use the PCI > bus as a multiplex bus between drives instead of SCSI. > > You're still pretty much stuck waiting for one command to finish before > another can be sent to a drive though, unlike SCSI drives. Still a lot > cheaper tho'. Not really, if the ATA drives are configured as single masters, they can run simultaniously, but you will still have the PCI bus speed limit :) Which BTW is around 120MB/s as some overhead goes to keep the system running (yes I have measured that :) ) And if you have modern ATA disks, they support tagged queuing as well, have had that running in my lab too... > I suppose another trick would be to arrange your vinum partitions and > drive layout so that master and slave drives are never accessed > simultaneously so one won't block access to the other. Endeed, that would be the easiest solution... -Søren To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200008182123.XAA80962>