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Example: Taking a Snapshot of the Software and Configuration
This example includes six scenarios in which you can take a snapshot of the currently running software and configuration on an ACX Series router, prior to the upgrade of an image or to remedy a bad image, thereby preventing the bad image from rendering the system useless.
Requirements
This example uses the following hardware and software components:
- One ACX Series router
- Junos OS Release 12.2 or later
Overview
In this example, the request system snapshot command is used to take a copy of the currently running software and configuration on another media—for example, a universal serial bus (USB) storage device, the active slice (da0s1 or da0s2) of a dual-root partitioned router, or the alternate slice (da0s1 or da0s2) of a dual-root partitioned router. A snapshot to another media ensures that the device can boot from the other media in case the system does not boot up from the current image.
 | Caution: After you run the request system snapshot command, you cannot return to the previous version of the software, because the running and backup copies of the software are identical. |
Taking a Snapshot
Step-by-Step Procedure
Scenario: To take a snapshot from a NAND flash device slice to a USB storage device:
- Boot up the router from the NAND flash device and make sure that a formatted USB storage device is plugged in to the router’s USB port. The USB storage device must be formatted for the root (/) and /config directories.
- Issue the request system snapshot command.
user@host> request system snapshotVerifying compatibility of destination media partitions... Running newfs (254MB) on usb media / partition (da1s1a)... Running newfs (47MB) on usb media /config partition (da1s1e)... Copying '/dev/da0s2a' to '/dev/da1s1a' .. (this may take a few minutes) Copying '/dev/da0s2e' to '/dev/da1s1e' .. (this may take a few minutes) The following filesystems were archived: / /config
The root (/) and /config directories from the currently mounted NAND flash slice are copied to the USB storage device.
Step-by-Step Procedure
Scenario: To take a snapshot from a NAND flash device slice to a USB storage device with formatting:
- Boot up the router from the NAND flash device and make
sure that a USB storage device is plugged in to the router’s
USB port.
Note: Formatting a USB storage device deletes all the data on the USB storage device.
- Issue the request system snapshot partition command.
user@host> request system snapshot partitionclearing current label... Partitioning usb media (da1) ... Partitions on snapshot: Partition Mountpoint Size Snapshot argument a / 312MB root-size e /config 47MB config-size f /var 620MB var-size Running newfs (312MB) on usb media / partition (da1s1a)... Running newfs (47MB) on usb media /config partition (da1s1e)... Running newfs (620MB) on usb media /var partition (da1s1f)... Copying '/dev/da0s2a' to '/dev/da1s1a' .. (this may take a few minutes) Copying '/dev/da0s2e' to '/dev/da1s1e' .. (this may take a few minutes) The following filesystems were archived: / /configAfter the USB storage device is formatted, the root (/) and /config directories from the currently mounted NAND flash slice are copied to the USB storage device.
Step-by-Step Procedure
Scenario: To take a snapshot from the active slice of the NAND flash device to the alternate slice:
- Boot up the router from the NAND flash device.
- Issue the request system snapshot slice alternate command.
user@host> request system snapshot slice alternateVerifying compatibility of destination media partitions... Running newfs (439MB) on internal media / partition (da0s1a)... Running newfs (46MB) on internal media /config partition (da0s1e)... Copying '/dev/da0s2a' to '/dev/da0s1a' .. (this may take a few minutes) Copying '/dev/da0s2e' to '/dev/da0s1e' .. (this may take a few minutes) The following filesystems were archived: / /config
The root (/) and /config directories from the currently mounted NAND flash slice are copied to the other slice.
Step-by-Step Procedure
Scenario: To take a snapshot from an active slice of the NAND flash device to the alternate slice after partitioning:
- Boot up the router from the NAND flash device.
- Issue the request system snapshot partition slice alternate command.
user@host> request system snapshot partition slice alternateVerifying compatibility of destination media partitions... Running newfs (439MB) on internal media / partition (da0s1a)... Running newfs (46MB) on internal media /config partition (da0s1e)... Copying '/dev/da0s2a' to '/dev/da0s1a' .. (this may take a few minutes) Copying '/dev/da0s2e' to '/dev/da0s1e' .. (this may take a few minutes) The following filesystems were archived: / /config
The BSD label (disk partitioning information) for the active flash slice is installed and then the root (/) and /config directories from the currently mounted NAND flash slice are copied to the other slice.
Step-by-Step Procedure
Scenario: To take a snapshot from a USB storage device to the active slice of the NAND flash device:
- Boot up the router from a USB storage device containing the required Junos OS image.
- Issue the request system snapshot command.
user@host> request system snapshotVerifying compatibility of destination media partitions... Running newfs (439MB) on internal media / partition (da0s1a)... Running newfs (46MB) on internal media /config partition (da0s1e)... Copying '/dev/da1s1a' to '/dev/da0s1a' .. (this may take a few minutes) Copying '/dev/da1s1e' to '/dev/da0s1e' .. (this may take a few minutes) The following filesystems were archived: / /config
The root (/) and /config directories from the USB storage device are copied to the active NAND flash slice.
Step-by-Step Procedure
Scenario: To take a snapshot from a USB storage device to the active slice of the NAND flash device after partitioning:
- Boot up the router from a USB storage device containing the required Junos OS image.
- Issue the request system snapshot partition command.
user@host> request system snapshot partitionVerifying compatibility of destination media partitions... Running newfs (439MB) on internal media / partition (da0s1a)... Running newfs (46MB) on internal media /config partition (da0s1e)... Copying '/dev/da1s1a' to '/dev/da0s1a' .. (this may take a few minutes) Copying '/dev/da1s1e' to '/dev/da0s1e' .. (this may take a few minutes) The following filesystems were archived: / /config
The BSD label (disk partitioning information) for the active flash slice is installed and then the root (/) and /config directories from the USB storage device are copied to the active NAND flash slice.
