---- Jon Peatfield <[log in to unmask]> wrote: 
> On Thu, 26 Jul 2007, Michael H. Semcheski wrote:
> 
> > So... I haven't gotten to a successful installation yet, but I think I
> > figured out what the problem was.
> >
> > I had a 3ware 9650se driving a 4x750 raid5.  What I forgot to was
> > carve (I think this is the term) a boot volume out of the main array.
> > That is, now I've got one 50GB drive, and one 2045GB drive, but they
> > have the same constituent drives.
> 
> Doesn't the 'standard' PC partition-table only allow access up to 2TB for 
> devices anyway?  I'd failed to spot that your total size ended up being 
> (just) over 2TB which probably causes all sorts of issues...
> 

I have a 6x500GB array on a 3ware9650SE running just fine as a single volume (2.3TB).  The partition type is 'ee' (EFI GPT) according to fdisk.  Although, fdisk is broken with this large of a volume.  Other tools such as sfdisk can handle them no problem.  df handles it just fine as well.  This is a debian 4 (etch) setup.
You may need to pre-partition the drive if the SL installer cannot handle it.

One difference with my setup is that I use a standalone 250GB drive for the OS.  I've never liked the idea of booting from a raid, although I do it standard for customers in a raid 1 configuration with 2x250GB drives on SL 4.1.

> On the boxes we have with larger raid setups, we are lucky enough that 
> they can all chop up the raidset into <2TB chunks which get presented to 
> the OS as seperate disks, which we can then join back together with LVM...
> 
> Apparently some raid devices can't do the chopping - I've heard this is 
> true of some megaraid cards but have never used them myself - at least not 
> for so long that 2TB was unthinkable at the time...
> 

This seems like an ugly hack.  One should not have to use LVM in conjunction with hardware raid.

> > PC's (as far as I know) can't boot off of a block device that holds
> > more than XGB, where X is > 50 but less than 2045.  Many RAID cards
> > allow you to create a smaller boot parition (which looks like a
> > seperate scsi disk to the OS) but is part of the main array.
> 

This is the first I've heard of 50GB < X < 2045GB causing problems.  Boot loaders, specifically LILO, had trouble in the past with booting from a partition beyond the 1024th cylinder, but that has long since been remedied.

> Support for >2TB devices is apparently possible at least with some 
> hardware/drivers but when I asked (a year or two ago - so it may be out of 
> date) I was strongly advised to avoid it for a while 'cos that code is new 
> and less well tested.  Anyway you need to use one of the new fancy 
> partition-table formats...
> 

Greater than 2TB devices/volumes are well supported with any modern kernel and should no longer be a problem.

> > Like I said, I haven't finished, because I'm in the process of
> > rebuilding the array.  But I'll bet thats what the problem was.
> 
> In another 12-24 months I guess single disks >2TB will be out and all 
> these things will need to work directly!
> 

Hope some of that helped!

Cheers,
Mark
--
----
Mr. Mark V. Stodola
Digital Systems Engineer
National Electrostatics Corp.
P.O. Box 620310
Middleton, WI 53562-0310 USA
Phone: (608) 831-7600
Fax: (608) 831-9591