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

Tom Judge tom at
Sun Jan 20 10:31:08 PST 2008

Erik Trulsson wrote:
> 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:

This post is related to using BSDLabel and FDISK MBR partition tables 
with a disk over 2Tb.  This is a known limitation of this type of 
partition table where the max size is 2Tb.  If you wish to make a larger 
partition you must use GPT or the raw device with no partition table 
(Not recommended!!!!).

>>> 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.

I have 5 PERC6/i based systems awaiting deployment atm, might be able to 
do some very limited testing on one of them if time permits.  However I 
have some very large arrays running on PERC5/e's (6TB Raid 50 - 5 disk 
spans - 15 * 500Gb disks spread over 2 md1000 shelves) (the systems run 
RELENG_6_2) and have not seem any issues with them.  They are a single 
gpt partition with UFS2 on them.....  As far as I have seen in the last 
~8 months there have been no issues with the mfi driver and large 
arrays.  However I cannot say at this stage if the same can be said for 
the PERC6/i.....

>> 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:

There is one related PCI ID's change to do with DELL sub vendor id's I 
think that is only on HEAD.  Any chance of getting this MFC'd?


>> 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.

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