On Sunday 20 January 2008 01:53:30 pm David Wood wrote: > Hi there, > > In message <[EMAIL PROTECTED]>, Erik > Trulsson <[EMAIL PROTECTED]> writes > >On Sun, Jan 20, 2008 at 04:48:56PM +0000, David Wood wrote: > >> In message <[EMAIL PROTECTED]>, > >> Aldas Nabazas <[EMAIL PROTECTED]> 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 _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "[EMAIL PROTECTED]"
