1 x 2 Backplane for our Pe2600

jason andrade jason at rtfmconsult.com
Sun Aug 31 23:02:00 CDT 2003

On Mon, 1 Sep 2003, Paul wrote:

> Dell came out to install a 1 x 2 Backplane for our Pe2600 yesterday and 2 x
> 36gb disks. The drives were installed in the media bay using their media bay
> converter. They were then connected to the second channel on the motherboard
> and left in standard SCSI mode. The first channel is in RAID mode with a
> RAID5 array on it. The dell guy then booted up went to the RAID bios and
> formatted the two new disks and then restarted the server. At this point the

if he went into the raid bios to 'format' the disks (what does this mean ?
he can't low level format the things.. maybe he initialized them ?) then
they are not on the scsi channel i am guessing, but on the raid channel.

> OS booted correctly but it couldn't see the new drives. I found the new
> backplane which was listed in dmesg and on the bootup screen but the drives
> were no where to be found. The OS is SuSe Linux Enterprise Server 8. So now
> we have the server running but can't use these two new disks. Is there
> anything simple I am missing to make this work?

the first thing is to verify the physical cabling to make sure it's all
ok.  i assume the drives in the media bay power up etc.

then check that the bios does indeed have the second channel as SCSI (and
not raid).

then check to see if you can see the drives as the system/bios level.  the
hardware should scan through the PERC (onboard) controller first and
see your raid arrays then the onboard scsi and see any devices connected
to it.

e.g perc blah blah
    aic7xxx blah blah

if you are not seeing the devices at the system/bios level then the OS will
not see it either.

> I assumed once they were formatted that I could simply fdisk /dev/sdb and
> away I go. But this is not the case. Below is stuff from dmesg if this helps
> work out whats wrong. Do I need some special compile of the MegaRAID driver
> now that I'm using each channel in a seperate mode? I wouldn't have thought
> so.

he may have initialized the drives but perhaps they have not been configured
as 'Volume' if they are on the raid channel.

> Attached scsi generic sg1 at scsi0, channel 4, id 6, lun 0,  type 3
> Attached scsi generic sg16 at scsi0, channel 5, id 6, lun 0,  type 3

hmm, these look like 'scsi generic' devices, not scsi disks. and on
different channels so i assume they're the 'system' scsi devices.

> Attached devices:
> Host: scsi0 Channel: 00 Id: 00 Lun: 00
>   Vendor: MegaRAID Model: LD0 RAID5 86390R Rev: 2.27
>   Type:   Direct-Access                    ANSI SCSI revision: 02

your PERC raid array.

> Host: scsi0 Channel: 04 Id: 06 Lun: 00
>   Vendor: PE/PV    Model: 1x6 SCSI BP      Rev: 0.29
>   Type:   Processor                        ANSI SCSI revision: 02

the backplane scsi

> Host: scsi0 Channel: 05 Id: 06 Lun: 00
>   Vendor: PE/PV    Model: 1x2 SCSI BP      Rev: 1.1
>   Type:   Processor                        ANSI SCSI revision: 02

the second backplane scsi

no sign of any disks..



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