raid or not raid

[Jerry McAllister]

On Thu, May 24, 2007 at 06:07:58AM -0500, illoai at gmail.com wrote:

> On 24/05/07, kalin mintchev <kalin at el.net> wrote:
> >
> >so nobody on this list knows anything about raid?
> >wrong list?
> >
> >> hi all..
> >>
> >> i have a box in a remote hosting facility that claims that the machine 
> >has
> >> two discs raided in it but df and fstab show only one disc with a bunch 
> >of
> >> slices.
> >> under devices there is another name - ad6 - but it's not mounted 
> >anywhere.
> >> the one i see both in df and the fstab is ad4 with one big slice and
> >> different partitions....
> >>
> >> they insist there are 2 raided discs in tha machine. the os is 5.4 and i
> >> think at that point the raid drivers were still considered 
> >'experimental'.
> >>
> >> it makes sense to me that if i don't see a second drive in the fstab 
> >there
> >> isn;t any mounting which means that there is no raid going on...
> >>
> >> is there any other way i can make sure if raid is actually on?
> >> would there will be any logs somewhere?
> >> the machine has been up for about 2 years and the dmesg is long gone...
> >>
> >> thanks.....
> >>
> 
> Lots of people here know plenty about RAID,
> but you don't provide very much information.
> 
> If dmesg itself returns none of the startup info,
> you can look in /var/log/dmesg.[today|yesterday].
> 
> /usr/sbin/pciconf can tell you what controller(s)
> may be attached.
> 
> A proper RAID will show up as a single device,
> just like any hard drive (but different).
> 
> It does seem odd to me that a (supposed) RAID
> would show up as /dev/ad4.

A hardware raid will look like any other drive to the system.
If it is SATA raid, it should be adN
It is it SAS raid, it should be daN.

Some systems allow you to address the drives as either individual
drives or as the raid - maybe until you have configured it or
something.   Anyway, on a Dell 2950 I could see both designations
but figured out which was the raid and used it and all was fine.

////jerry

> 
> Possibilities:
> Your RAID really is on /dev/ad4 and /dev/ad6 is
> something unexplained.
> Your RAID controller is unsupported in 5.x and
> not Doing The Right Thing but somehow still (kind
> of) working as a normal [S]ATA controller.
> Your RAID controller is unsupported in 5.x and
> your hosting company realised this and wired
> the shebang up as a normal [S]ATA controller
> because they couldn't get FreeBSD to install
> otherwise.
> There is a RAID controller and there are two disks
> connected to it, but the controller was not set up
> correctly.
> There is a RAID controller and there are two disks
> connected to some other controller which might lead
> to some interesting phone calls.
> Your remote hosting company put a RAID with two
> disks in some random machine and someone else
> is complaining on some other list about the inverse
> of your problem.
> 
> -- 
> --
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