Before upgrading Junos OS on a POP router that has no on-site spare, a cautious engineer wants a bootable backup copy of the current, known-working software and configuration on backup storage media, so the router can be recovered quickly if the upgrade goes wrong. Which command creates that backup?
Select an answer to reveal the explanation.
Short Explanation
It's the same instinct as cloning a hard drive before a risky operating-system update — if the new install goes sideways, you want a known-good copy to fall back to. request system snapshot is that clone for a router: a bootable backup of the current software and configuration on backup media.
Full Explanation
request system snapshot copies the currently running Junos OS software and active configuration onto backup storage media (an alternate slice, on platforms that support it), producing a bootable known-good backup that can restore service quickly if a subsequent upgrade fails — exactly the safety net a cautious engineer wants before touching a POP router with no on-site spare hardware. request system software validate <package> is a genuinely useful earlier step in an upgrade workflow, but it only checks the new package's compatibility; it makes no backup copy of the current, working state. show system storage merely reports filesystem free space and creates nothing. request system storage cleanup actively removes old, unneeded files to reclaim space — the opposite intent of creating a preservation copy, and running it carelessly could even remove something useful before a snapshot is taken. A caveat: a snapshot reflects the state at the moment it's taken, so it should be run immediately before the upgrade, not days earlier, to guarantee it matches the last known-working configuration. A concrete check: confirm the snapshot completed successfully and note which backup slice it targeted before proceeding with the software install.