Error: usb (/dev/da0) media missing or invalid on ACX5000

Summary:

Due to the absence of NAND flash on the ACX5000 series routers, the command, 'request system snapshot slice alternate' will look to copy the active partitions to the USB.
If the USB ports are empty, then the command will fail and return an error.

Symptoms:

On ACX5048 or ACX5096, the command 'request system snapshot slice alternate' returns the following error:

{master:0} lab@R1> request system snapshot slice alternate fpc0: ------------------------------------------------ error: usb (/dev/da0) media missing or invalid

Cause:

The ACX5000 series devices do not have a NAND flash built-in to the routing engine.

The following command shows that there is no NAND flash on the ACX5048 router:

{master:0} lab@R1> show chassis hardware detail Hardware inventory: Item Version Part number Serial number Description Chassis WC3715300006 ACX5096 Pseudo CB 0 Routing Engine 0 BUILTIN BUILTIN ACX5K Routing Engine ad0 509 MB QEMU HARDDISK QM00001 Hard Disk ad1 4095 MB QEMU HARDDISK QM00002 Hard Disk ad2 511 MB QEMU HARDDISK QM00003 Hard Disk ad3 1023 MB QEMU HARDDISK QM00004 Hard Disk usb0 (addr 1) product 0x0000 0 vendor 0x0000 uhub1 usb0 (addr 2) product 0x0020 32 vendor 0x8087 uhub2

Output from ACX2000 series router, that shows NAND flash is built-in to the routing-engine:

lab@R1> show chassis hardware detail Hardware inventory: Item Version Part number Serial number Description Chassis HS0212511608 ACX2000 Midplane REV 12 650-037055 HS0212511608 ACX2000 Routing Engine BUILTIN BUILTIN Routing Engine da0 3820 MB USB DISK 2.0 Nand Flash 0 FEB 0 BUILTIN BUILTIN Forwarding Engine Processor

The command, 'request system snapshot slice alternate' by default, looks for a NAND flash to copy the running configuration and Junos:

lab@R1> request system snapshot slice alternate Doing the initial labeling... Verifying compatibility of destination media partitions... Running newfs (439MB) on internal media / partition (da0s2a)... Running newfs (46MB) on internal media /config partition (da0s2e)... Copying '/dev/da0s1a' to '/dev/da0s2a' .. (this may take a few minutes) Copying '/dev/da0s1e' to '/dev/da0s2e' .. (this may take a few minutes) The following filesystems were archived: / /config

As seen above, active partitions are copied to the internal media, which is da0 (nand flash).

Solution:

Due to the absence of NAND flash on the ACX5000 series routers, the command, 'request system snapshot slice alternate' will look to copy the active partitions to the USB.
If the USB ports are empty then the command will fail resulting in the following error message

{master:0} lab@R1> request system snapshot slice alternate fpc0: ----------------------------------------------- error: usb (/dev/da0) media missing or invalid

To solve this issue, a USB must be inserted into one of the 2 USB ports so that the active partitions are copied to the USB.

The following output shows a USB inserted into one of the 2 USB slots:

{master:0} lab@R1> #umass0: Unigen Corporation PQS4000B8-JNP, rev 2.00/11.00, addr 3 inserted USB Mar 02 11:02:43 {master:0} lab@R1> da0 at umass-sim0 bus 0 target 0 lun 0 da0: <Unigen PQS4000 1100> Removable Direct Access SCSI-0 device da0: 40.000MB/s transfers da0: 3824MB (7831552 512 byte sectors: 255H 63S/T 487C)

Now, when the command is executed, it does not return the error message and the active partitions are successfully copied to the USB as shown below:

{master:0} lab@R1> request system snapshot slice alternate fpc0: ------------------------------------------------------------------------ -- Starting snapshot to usb (/dev/da0) Creating snapshot on the host .. umass0: at uhub2 port 2 (addr 3) disconnected (da0:umass-sim0:0:0:0): lost device (da0:umass-sim0:0:0:0): removing device entry umass0: detached Copying bootable disk image from host ..

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