Date: Sat, 15 Sep 2001 20:56:45 +0200 From: Bernd Walter <ticso@mail.cicely.de> To: Matthew Jacob <mjacob@feral.com> Cc: Don Sullivan <sullivan@gaia.arc.nasa.gov>, freebsd-hackers@FreeBSD.ORG Subject: Re: Large disk (>1 TB) support in FBD4.3 ? Message-ID: <20010915205645.C17960@cicely20.cicely.de> In-Reply-To: <Pine.BSF.4.21.0109151125080.9267-100000@beppo>; from mjacob@feral.com on Sat, Sep 15, 2001 at 11:29:41AM -0700 References: <Pine.GSO.4.40.0109151111110.1130-100000@durga.arc.nasa.gov> <Pine.BSF.4.21.0109151125080.9267-100000@beppo>
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On Sat, Sep 15, 2001 at 11:29:41AM -0700, Matthew Jacob wrote: > > Don- too bad- I'm over in NAS in building N-258 and just took down the h/w > where we could test this (Alpha 4100 with 8 Qlogic cards && 8 150GB MegaDrive > RAID arrays)- We're excessing this equipment because the mass storage group's > work was terminated due to budgetary goop. > > Typically there's no problem in *recognizing* raw SCSI disk, or RAID units > that look like a SCSI disks- Mike or others will have to speak about how well > specifical supported RAID cards for FreeBSD will handle something that large. I'm not shure about recent SCSI definitions, but as long as a physical sector is sized at 512 Bytes and SCSI uses 32Bit unsigned numbers a (virtual) SCSI disk is limited to 2T. Maybe recent SCSI specs already defined a new set of read/write... > A more problematic issue is whether FFS can reliably handle > 1TB. We did some > tests with NetBSD at 1TB a couple of years ago- you have to use larger block > and frag sizes (we were using 32k/8k)- but I've never myelf gotten FreeBSD up > above 500GB. I was going to do so when the rather flakey h/w I was on above > was set to be excessed. If I'd known you needed the work done- I could have > kept it going a couple more weeks and we could worked on sorting it out. FFS in it's design can go up to 2G * fragsize - that means 2T with default fragsize of 1k. The Problem is that FreeBSD internaly uses 32bit signed Blocknumbers for 512Bytes/Block independend of it's physical size. This limits to 1T. I successfully build 600G partitions with vinum and I've heared of users running partitions near the 1T limit. -- B.Walter COSMO-Project http://www.cosmo-project.de ticso@cicely.de Usergroup info@cosmo-project.de To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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