installed new hard drive - now can't find it

[Rick Stevens]

Dana Holland wrote:
> We just installed a new SCSI hard drive in our Dell box - it was the 4th 
> of a 4-drive chain.  We're running RH 7.3 on the box.  During boot up we 
> see that it recognizes the new device, but it doesn't give any kind of 
> label or anything else to identify the new drive.  After the system 
> boots up, we can't find the drive to partition it.  How do I find it?

Examine the /var/log/dmesg and /var/log/messages files.  In
/var/log/dmesg, you should see something like this for EACH SCSI drive
in your machine:

(scsi0:A:0): 320.000MB/s transfers (160.000MHz DT|IU|RTI|QAS, 16bit)
   Vendor: FUJITSU   Model: MAP3147NC         Rev: 0105
   Type:   Direct-Access                      ANSI SCSI revision: 03
blk: queue c4693818, I/O limit 4095Mb (mask 0xffffffff)
scsi0:A:0:0: Tagged Queuing enabled.  Depth 32
Attached scsi disk sda at scsi0, channel 0, id 0, lun 0
SCSI device sda: 287132440 512-byte hdwr sectors (147012 MB)
              ^
              |-- Take note of that

Look in that bunch of messages to look for the vendor name and model of
the drive you're looking for.  If you don't see it, then there's
something going on with your SCSI configuration.  If you do see it, note
own the stuff I indicated above.  That's the name under "/dev" for the
raw device (the above example is "/dev/sda").

Some SCSI notes:

1.	On SCSI-I and SCSI-II (8-target) buses, typically the controller
	is SCSI ID 7 and you may NOT set a device's ID to that value.

2.	On SCSI-III and later (16-target) buses, the controller is also
	usually SCSI ID 7, but may be SCSI ID 15, depending on the
	vendor.  You may not set a device's ID to the same as the SCSI
	controller, EVER.

3.	Verify your bus termination.  The devices at the ENDS of the bus
	must be terminated, NOTHING ELSE may be terminated.  Controllers
	are generally terminated and should be at one end of the cable.
	The drive at the other end should also be terminated and the
	termination disabled on all other drives.

4.	If you must put the controller in the middle of a cable, you
	must get into the SCSI BIOS and disable the controller's
	termination, then make sure the devices at the end of the cable
	are terminated.

5.	Make sure of your cable and its length.  SCSI is rarely reliable
	if the cable length goes above 1 meter in length (~3 feet).

Hope that helps a bit.
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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-              Death is nature's way of dropping carrier             -
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