Dell Perc 6 disk geometry problem with RAID5 (both 6.3 final and 7.0 RC1)

Erik Trulsson ertr1013 at
Sun Jan 20 09:58:27 PST 2008

On Sun, Jan 20, 2008 at 04:48:56PM +0000, David Wood wrote:
> [ambrisko@ and scottl@ added to CCs]
> Hi there,
> In message <9c1614e00801200608k49195944mf241b7b0aa6a48 at>, 
> Aldas Nabazas <freebsd.stable1 at> 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:
>> I was reading the mailing list and found that some of the people are happily
>> using this hardware with the latest FreeBSD:
>> I just wonder what the status of mfi driver? Maybe it's not fully tested or
>> there will be some important fixes before 7.0 final? We are going to try
>> different RAID combinations but it definitely not working using 6x146GB as
>> RAID5.

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.

> This is extremely disappointing to read, as I was relatively close to 
> buying a Poweredge 2950 III with PERC 6/i. However, it's no good to me if 
> mfi(4) has issues with large virtual disks; the tentative disk 
> configuration is 2x146GB as RAID 1 and 4x750GB (or 1TB) as RAID 5.
> Looking at CVSweb:
> the updates for the 1078 chip which powers the PERC 6 series were 
> contributed by LSI, so you would have hoped things were right. There is a 
> disclaimer on the code, but you would also hope that someone in the know is 
> testing it, especially as my impression has always been that the FreeBSD 
> community is favourably disposed towards LSI storage controllers and that 
> LSI and their vendors try to help the FreeBSD developers.
>> Maybe someone could share the RAID combinations they successfully are
>> running on?
> I haven't been keeping a very close eye on the problem as I don't currently 
> have any hardware - but is the issue simply one of virtual disk size - 
> there's a cut-off size after which things don't work properly?
> You could try pulling disks from your server (or removing them from the 
> virtual disk) one by one until things start to work. To save a lot of pain 
> you could create a virtual disk containing one disk as RAID 0 (a single 
> disk) and install the OS on it, leaving the other five disks to play with.
> I do hope that someone is in a position to investigate this quickly - even 
> if it's too late to get the fix in 7.0-RELEASE now. There's nothing that I 
> can see as relevant that's waiting for MFC, anyway.
> Of course, it's worth checking whether you've got the latest firmware on 
> the PERC 6/i - the latest version from Dell appears to be 6.0.1-0080.
> If this doesn't get fixed soon, I'm either going to have to go to another 
> hardware vendor that uses a different RAID controller (HP is a possibility 
> - though we're an all Dell shop) or - sniff - leave FreeBSD in favour of a 
> Linux distribution. I realise that FreeBSD is a volunteer project, and that 
> users can't have any specific expectations - this is not a threat, as I 
> like FreeBSD and want to remain in the community, but I would need a new 
> server to work properly!
> Looking at CVSweb, it seems that ambrisko@ and scottl@ are the two people 
> most closely associated with the mfi code - I've added them into the CCs. 
> My apologies if that was unwelcome.

<Insert your favourite quote here.>
Erik Trulsson
ertr1013 at

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