Date: Sat, 11 Oct 2008 07:48:17 -0700 From: Jeremy Chadwick <koitsu@FreeBSD.org> To: Gary Jennejohn <gary.jennejohn@freenet.de> Cc: freebsd-stable@freebsd.org, JoaoBR <joao@matik.com.br>, freebsd-amd64@freebsd.org Subject: Re: am2 MBs - 4g + SCSI wipes out root partition Message-ID: <20081011144817.GB64861@icarus.home.lan> In-Reply-To: <20081011164529.198f32c6@ernst.jennejohn.org> References: <200810101429.37244.joao@matik.com.br> <20081011113057.7402300c@ernst.jennejohn.org> <20081011101316.GA58119@icarus.home.lan> <20081011164529.198f32c6@ernst.jennejohn.org>
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On Sat, Oct 11, 2008 at 04:45:29PM +0200, Gary Jennejohn wrote: > On Sat, 11 Oct 2008 03:13:16 -0700 > Jeremy Chadwick <koitsu@FreeBSD.org> wrote: > > > On Sat, Oct 11, 2008 at 11:30:57AM +0200, Gary Jennejohn wrote: > > > On Fri, 10 Oct 2008 14:29:37 -0300 > > > JoaoBR <joao@matik.com.br> wrote: > > > > > > > I tried MBs as Asus, Abit and Gigabyte all same result > > > > > > > > Same hardware with SATA works perfect > > > > > > > > Same hardware with scsi up to 3.5Gigs installed works perfect > > > > > > > > what calls my attention that all this MBs do not have the memroy hole > > > > remapping feature so the complete 4gigs are available what normally was not > > > > the case with amd64 Mbs for the Athlon 64 CPUs > > > > > > > > some has an opinion if this is a freebsd issue or MB falure or scsi drv > > > > problem? > > > > > > > > > > It's a driver problem. If you want to use SCSI then you'll have to limit > > > memory to 3.5 GB. > > > > What you're saying is that Adaptec and LSI Logic SCSI controllers behave > > badly (and can cause data loss) on amd64 systems which contain more than > > 3.5GB of RAM. This is a very big claim. > > > > Have you talked to Scott Long about this? > > > > Please expand on this, and provide evidence or references. I need to > > document this in my Wiki if it is indeed true. > > > > See the freebsd-scsi thread with Subject "data corruption with ahc driver > and 4GB of memory using a FBSD-8 64-bit installation?" from Wed, 30 Jan > 2008. > > This was for ahc, but the bit-rot which Scott mentions in his reply might > also apply to the LSI Logic controllers. > > Basically the driver doesn't correctly handle DMA above 4GB. Since the PCI > hole gets mapped above 4GB it causes problems. the (S)ATA drivers don't seem > to have this problem. Thank you -- this is the exact information I was looking for. I will update my Wiki page to reflect this quite major problem. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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