raid or not raid

[Jack Barnett]

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.
>
> 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.
>
Also what type of RAID?  If it's Hardware RAID _and_ it's using a 3ware 
card, you can install tw_cli from /usr/ports/sysutils.  It's a nice 
little utility and will show you the status of your units/ports/drives 
and how many drives you have on that controller.