raid or not raid

[Ted Mittelstaedt]

> -----Original Message-----
> From: owner-freebsd-questions at freebsd.org
> [mailto:owner-freebsd-questions at freebsd.org]On Behalf Of kalin mintchev
> Sent: Thursday, May 24, 2007 4:11 PM
> To: freebsd-questions at freebsd.org
> Cc: rsmith at xs4all.nl
> Subject: Re: raid or not raid
>
>
> > On Thu, May 24, 2007 at 06:30:06AM -0400, kalin mintchev 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....
> >
> > My (VIA Tech V-RAID) raid disk shows up as ar0, although the ad4 and ad6
> > device nodes exist as well.
> >
> > Do you have the ataraid device in the kernel?
>
> yes. but isn;t that in by default in 5.4 GENERIC?!
>
> >> > 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'.
> >
> > Then ask them how it's done.
> >
> >> > 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...
> >
> > If you're seeing an ad device, it's not RAID-ed, AFAIK.
> >
> >> > 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...
> >
> > It should be in /var/run/dmesg.boot.
>
> thanks. i guess that solves the ad6 mistery:
>
> atapci0: <Intel ICH5 UDMA100 controller> port
> 0xfc00-0xfc0f,0x376,0x170-0x177,0x3f6,0x1f0-0x1f7 at device 31.1 on pci0
> ata0: channel #0 on atapci0
> ata1: channel #1 on atapci0
> atapci1: <Intel ICH5 SATA150 controller> port
> 0xcc80-0xcc8f,0xcc98-0xcc9b,0xcca0-0xcca7,0xccb0-0xccb3,0xccb8-0xccbf irq
> 18 at device 31.2 on pci0
> ata2: channel #0 on atapci1
> ata3: channel #1 on atapci1
> .....................................................
> ad4: 152587MB <WDC WD1600JS-75MHB0/03.01C03> [310019/16/63] at ata2-master
> SATA150
> ad6: 152587MB <WDC WD1600JS-75MHB0/03.01C03> [310019/16/63] at ata3-master
> SATA150
> Mounting root from ufs:/dev/ad4s1a
>
> unless "at device 31.2 on pci0" points to some RAID evidence - which i
> think it's false - than i read this as the ad6 disk sits there unused.
> am i right?!
>
> according to pciconf the atapci0 and atapci1 are differnt conrollers -
> EIDE and SATA so they can both be on pci0 as 31.1 and 31.2?! still no RAID
> though...
>

I've come late to this thread but it's been interesting watching the
speculation.

Yes, they F'd up the installation.  Badly.  But you need to back up every
scrap of data before trying to fix it.  And use FBSD 6.2 on the next one.
There's been lots of driver fixes in the ata driver that you want.

ata raid should show all your data on AR not AD!!  Here's an example
from my mailserver:

mail# cat /etc/fstab
# Device                Mountpoint      FStype  Options         Dump
Pass#
/dev/ar0s1b             none            swap    sw              0       0
/dev/ar0s1a             /               ufs     rw              1       1
/dev/ar0s1e             /usr            ufs     rw              2       2
/dev/ar0s1d             /var            ufs     rw              2       2
/dev/acd0               /cdrom          cd9660  ro,noauto       0       0
mail#

Also, note the following.  VERY important!

When you go to setup a RAID mirror on a system, using a UDMA or SATA
controller,
(ie: NOT using a RAID5 card or SCSI card or some such) here is what you do.

Start by going into the system RAID BIOS on boot, setup your RAID, then
boot the install disk.  Disks ad4 and ad6 will always show.  If disk ar0
also shows, you can select ar0 and install to that.

IF DISK ar0 DOES NOT SHOW, then your BIOS "metadata" isn't compatible. STOP.
Reboot system.  GO into BIOS.  DESELECT and DISABLE the RAID.

Boot system with install CD.  At the screen that displays ad4 and ad6,
select
ad4.  Select Minimal install.  Don't bother answering any post install
questions.
Finish install.  Reboot and login to root.  At command line, issue command:

atacontrol create RAID1 ad4 ad6

Immediately reboot from the install CD.  Now, at the disk selection screen
you will see ar0.  Select this.  Delete all existing partitions and recreate
them, install the full system and your in business.

Ted