Date: Wed, 23 Jan 2008 15:29:29 +0000 From: "Aldas Nabazas" <freebsd.stable1@gmail.com> To: freebsd-stable@freebsd.org Subject: Re: Dell Perc 6 disk geometry problem with RAID5 (both 6.3 final and 7.0 RC1) Message-ID: <9c1614e00801230729w508f309yada1272e499dff23@mail.gmail.com> In-Reply-To: <200801230919.23681.jhb@freebsd.org> References: <9c1614e00801200608k49195944mf241b7b0aa6a48@mail.gmail.com> <20080120175819.GA52965@owl.midgard.homeip.net> <35cWA$Gqi5kHFAjh@wood2.org.uk> <200801230919.23681.jhb@freebsd.org>
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On Jan 23, 2008 2:19 PM, John Baldwin <jhb@freebsd.org> wrote: > On Sunday 20 January 2008 01:53:30 pm David Wood wrote: > > Hi there, > > > > In message <20080120175819.GA52965@owl.midgard.homeip.net>, Erik > > Trulsson <ertr1013@student.uu.se> writes > > >On Sun, Jan 20, 2008 at 04:48:56PM +0000, David Wood wrote: > > >> In message <9c1614e00801200608k49195944mf241b7b0aa6a48@mail.gmail.com > >, > > >> Aldas Nabazas <freebsd.stable1@gmail.com> writes > > >>> We bought a new Dell PowerEdge 2950III with Perc 6/i and have the > disk > > >>> geometry problem using 6.3 final or 7.0 RC1. Seems that we are not > alone at > > >>> least one guy has similar problem reported earlier: > > >>> > > >>> > http://unix.derkeiler.com/Mailing-Lists/FreeBSD/questions/2008-01/msg0 > > >>>0506.html > > > > > >I do not know if the mfi(4) driver has any problems with large disks, > but it > > >is however well known that fdisk(8) and bsdlabel(8) (the tools normally > used > > >to partition disks) have problems with volumes larger than 2TB. > > > > > >If you want to use volumes larger than 2TB then gpt(8) is the > recommended > > >way to partition the disks. It is however doubtful if the BIOS in your > > >system will allow you to boot from a gpt(8) parttioned volume which is > > >best solved with having a separate - smaller - boot volume where the OS > > >itself is installed. > > > > Erik's reminder is timely for those with >2TB volumes. > > > > You must use gpt and not fdisk on any disk, be it a single drive (in the > > future, at least!) or a virtual disk on a RAID setup that are bigger > > than 2TB. It may be wise to use gpt on any virtual disk that you might > > grow to 2TB or larger in the future, so long as you're not needing to > > boot from that virtual disk. > > > > fdisk will not work properly with 2TB and larger volumes - the MBR / > > partition table setup can't cope with these large volumes. > > > > > > You can't boot from a GPT volume - that's a limitation of the BIOS > > architecture. There is some thought about using EFI on x64 hardware in > > the future (EFI is used on ia64 hardware; GPT is part of EFI), but we're > > not there yet. This isn't just about adding GPT support to the BIOS - > > the whole BIOS setup is wedded to MBR. > > > > If you need to boot from a >2TB array, create two virtual disks - one > > smaller than 2TB to boot from (and use MBR on that), then the residue > > can be GPT. > > Actually, using gptboot in HEAD you can now boot from GPT on large volumes > (I've booted from a > 2 TB volume on a PERC5 using mfi(4) with it). I > will see about getting that merged back to 6.x and 7.x in CVS. We use > it for large volumes on 6.x and all volumes on 7.x at work. > > > When I said there was nothing relevant waiting for MFC, I was aware of > > the change that Tom mentioned, but that seems to be about Dell PERC 6 > > being identified as such rather than a MegaRAID. It doesn't seem that it > > will change the behaviour of the driver in any way. > > In our testing at work the 2950 rev 3's worked fine with mfi(4). > > -- > John Baldwin > Hi John, Nice to hear that. Regards, Aldas
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