Date: Wed, 5 Feb 2003 18:53:49 +0200 (EET) From: Narvi <narvi@haldjas.folklore.ee> To: "Brandon D. Valentine" <brandon@dvalentine.com> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Network block device. Message-ID: <20030205155452.U43637-100000@haldjas.folklore.ee> In-Reply-To: <20030129235040.GY16038@geekpunk.net>
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[cc: reduced] On Wed, 29 Jan 2003, Brandon D. Valentine wrote: > On Wed, Jan 29, 2003 at 06:06:20PM -0500, Matthew N. Dodd wrote: > > > > What you really want is SCSI over IP. Anything else is just a hack and > > not to be trusted. I think that NFS is less of a hack than NBD though. > > IMO NBD is less of a hack than you think it is. It is one of the > necessary components for creating a single system image from a cluster > of commodity hardware and this is something Linux developers are working > earnestly on. They're targeting a poor man's NUMA. In this case the A cluster - no matter how transparently it has a single system image - is not a NUMA. DSM is not really NUMA either, and not all that many things really benefit from DSM - most things aplicable to DSM run better if you use a combination of messgae passing and io/function shipping instead. But going to NBD is a flawed idea in that unless you are planning to use it for a database that can manage its own locking you are better off with a file system instead. > idea is that each node [network] boots a very minimal operating system > image which acts as a slave to the master node, making its hardware > (disks in this case) available via some interconnect using network block > devices. Then the operating system on the master node can mount the > devices under one unified /. OpenMosix is working on solving the other > parts of the puzzle, which are scheduling and cache/memory coherency. > Myrinet is rapidly converging on SGI's CrayLink interconnect as a > low-latency memory bus, making this possible in the next few years on PC > hardware. > MyriNet is not a memory bus - its a fast message passing interface. You can use it to imnplement DSM (big suprise, you can with 10Mbit ethernet aswell) but it doesn't have the hardware you would need to actually make use of it as ccNUMA. > Brandon D. Valentine > -- > brandon@dvalentine.com http://www.geekpunk.net > > "We've been raised on replicas of fake and winding roads, and day after day up > on this beautiful stage we've been playing tambourine for minimum wage, but we > are real; I know we are real." -- David Berman > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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