Marianne
I've accordingly added the term "VERBOSE" in the vm.conf.
Before:
MM_SERVER_NAME = RD-BMO-BCK01
~
~
~
~
After:
MM_SERVER_NAME = RD-BMO-BCK01
VERBOSE
~
~
~
Then I've restarted the NBU with the 2 commands.
Result: in the "Device Monitor" section the HP.ULTRIUM5-SCSI.001 drive is down and I cannot put it UP (even if I do a right-click on and select UP).

I'd a look in /var/log/messages which is below (this is a short extract, if you want I can provide you the full file).
Feb 18 12:33:02 RD-BMO-BCK01 tldd[49131]: TLD(0) unavailable: initialization failed: Unable to open robotic path
Feb 18 12:35:05 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00P
Feb 18 12:35:05 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:35:05 RD-BMO-BCK01 tldcd[49160]: tldcd.c.3039, process_request(), received command=9, from peername=RD-BMO-BCK01, version 50
Feb 18 12:35:05 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00P
Feb 18 12:35:05 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:35:05 RD-BMO-BCK01 tldd[49131]: DecodeQuery() Actual status: Unable to open robotic path
Feb 18 12:35:05 RD-BMO-BCK01 tldd[49131]: TLD(0) unavailable: initialization failed: Unable to open robotic path
Feb 18 12:37:07 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00P
Feb 18 12:37:07 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:37:07 RD-BMO-BCK01 tldcd[49160]: tldcd.c.3039, process_request(), received command=9, from peername=RD-BMO-BCK01, version 50
Feb 18 12:37:07 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00P
Feb 18 12:37:07 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:37:07 RD-BMO-BCK01 tldd[49131]: DecodeQuery() Actual status: Unable to open robotic path
Feb 18 12:37:07 RD-BMO-BCK01 tldd[49131]: TLD(0) unavailable: initialization failed: Unable to open robotic path
Feb 18 12:39:09 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00P
Feb 18 12:39:09 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:39:09 RD-BMO-BCK01 tldcd[49160]: tldcd.c.3039, process_request(), received command=9, from peername=RD-BMO-BCK01, version 50
Feb 18 12:39:09 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00P
Feb 18 12:39:09 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:39:09 RD-BMO-BCK01 tldd[49131]: DecodeQuery() Actual status: Unable to open robotic path
Feb 18 12:39:09 RD-BMO-BCK01 tldd[49131]: TLD(0) unavailable: initialization failed: Unable to open robotic path
Feb 18 12:41:11 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00P
Feb 18 12:41:11 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:41:11 RD-BMO-BCK01 tldcd[49160]: tldcd.c.3039, process_request(), received command=9, from peername=RD-BMO-BCK01, version 50
Feb 18 12:41:11 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00P
Feb 18 12:41:11 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:41:11 RD-BMO-BCK01 tldd[49131]: DecodeQuery() Actual status: Unable to open robotic path
Feb 18 12:41:11 RD-BMO-BCK01 tldd[49131]: TLD(0) unavailable: initialization failed: Unable to open robotic path
Feb 18 12:43:13 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00P
Feb 18 12:43:13 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:43:13 RD-BMO-BCK01 tldcd[49160]: tldcd.c.3039, process_request(), received command=9, from peername=RD-BMO-BCK01, version 50
Feb 18 12:43:13 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00P
Feb 18 12:43:13 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:43:13 RD-BMO-BCK01 tldd[49131]: DecodeQuery() Actual status: Unable to open robotic path
Feb 18 12:43:13 RD-BMO-BCK01 tldd[49131]: TLD(0) unavailable: initialization failed: Unable to open robotic path
Feb 18 12:45:15 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00P
Feb 18 12:45:15 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:45:15 RD-BMO-BCK01 tldcd[49160]: tldcd.c.3039, process_request(), received command=9, from peername=RD-BMO-BCK01, version 50
Feb 18 12:45:15 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00P
Feb 18 12:45:15 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:45:15 RD-BMO-BCK01 tldd[49131]: DecodeQuery() Actual status: Unable to open robotic path
Feb 18 12:45:15 RD-BMO-BCK01 tldd[49131]: TLD(0) unavailable: initialization failed: Unable to open robotic path
Feb 18 12:45:30 RD-BMO-BCK01 kernel: usb 2-1.5: new high speed USB device number 4 using ehci_hcd
Feb 18 12:45:30 RD-BMO-BCK01 kernel: usb 2-1.5: New USB device found, idVendor=18a5, idProduct=0302
Feb 18 12:45:30 RD-BMO-BCK01 kernel: usb 2-1.5: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Feb 18 12:45:30 RD-BMO-BCK01 kernel: usb 2-1.5: Product: STORE N GO
Feb 18 12:45:30 RD-BMO-BCK01 kernel: usb 2-1.5: Manufacturer: Verbatim
Feb 18 12:45:30 RD-BMO-BCK01 kernel: usb 2-1.5: SerialNumber: 1402000000000002
Feb 18 12:45:30 RD-BMO-BCK01 kernel: usb 2-1.5: configuration #1 chosen from 1 choice
Feb 18 12:45:30 RD-BMO-BCK01 kernel: Initializing USB Mass Storage driver...
Feb 18 12:45:30 RD-BMO-BCK01 kernel: scsi4 : SCSI emulation for USB Mass Storage devices
Feb 18 12:45:30 RD-BMO-BCK01 kernel: usbcore: registered new interface driver usb-storage
Feb 18 12:45:30 RD-BMO-BCK01 kernel: USB Mass Storage support registered.
Feb 18 12:45:31 RD-BMO-BCK01 kernel: scsi 4:0:0:0: Direct-Access Verbatim STORE N GO 1.01 PQ: 0 ANSI: 2
Feb 18 12:45:31 RD-BMO-BCK01 kernel: sd 4:0:0:0: Attached scsi generic sg4 type 0
Feb 18 12:45:31 RD-BMO-BCK01 kernel: sd 4:0:0:0: [sdb] 7831552 512-byte logical blocks: (4.00 GB/3.73 GiB)
Feb 18 12:45:31 RD-BMO-BCK01 kernel: sd 4:0:0:0: [sdb] Write Protect is off
Feb 18 12:45:31 RD-BMO-BCK01 kernel: sd 4:0:0:0: [sdb] Assuming drive cache: write through
Feb 18 12:45:31 RD-BMO-BCK01 kernel: sd 4:0:0:0: [sdb] Assuming drive cache: write through
Feb 18 12:45:31 RD-BMO-BCK01 kernel: sdb: sdb1
Feb 18 12:45:31 RD-BMO-BCK01 kernel: sd 4:0:0:0: [sdb] Assuming drive cache: write through
Feb 18 12:45:31 RD-BMO-BCK01 kernel: sd 4:0:0:0: [sdb] Attached SCSI removable disk
Feb 18 12:45:31 RD-BMO-BCK01 kernel: uhci_hcd 0000:01:00.4: Controller not stopped yet!
Feb 18 12:46:43 RD-BMO-BCK01 SQLAnywhere(nb_rd-bmo-bck01): Starting checkpoint of "NBAZDB" (NBAZDB.db) at Thu Feb 18 2016 12:46
Feb 18 12:46:43 RD-BMO-BCK01 SQLAnywhere(nb_rd-bmo-bck01): Starting checkpoint of "NBDB" (NBDB.db) at Thu Feb 18 2016 12:46
Feb 18 12:46:43 RD-BMO-BCK01 SQLAnywhere(nb_rd-bmo-bck01): Finished checkpoint of "NBAZDB" (NBAZDB.db) at Thu Feb 18 2016 12:46
Feb 18 12:46:43 RD-BMO-BCK01 SQLAnywhere(nb_rd-bmo-bck01): Finished checkpoint of "NBDB" (NBDB.db) at Thu Feb 18 2016 12:46
Feb 18 12:47:17 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00P
Feb 18 12:47:17 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:47:17 RD-BMO-BCK01 tldcd[49160]: tldcd.c.3039, process_request(), received command=9, from peername=RD-BMO-BCK01, version 50
Feb 18 12:47:17 RD-BMO-BCK01 tldcd[49160]: TLD(0) opening robotic path MISSING_PATH:MXA338Z00
Feb 18 12:47:17 RD-BMO-BCK01 tldcd[49160]: TLD(0) [49160] robotic path MISSING_PATH:MXA338Z00P does not exist
Feb 18 12:47:17 RD-BMO-BCK01 tldd[49131]: DecodeQuery() Actual status: Unable to open robotic path
Feb 18 12:47:17 RD-BMO-BCK01 tldd[49131]: TLD(0) unavailable: initialization failed: Unable to open robotic path