Upgrading to 64-bit Junos OS
Just like any other operating system, the 64-bit version of Junos OS can address more memory than the 32-bit version of the operating system. In order to support larger Routing Engine memory sizes, an upgrade from the 32-bit to the 64-bit Junos OS running on the Routing Engine hardware is necessary. The upgrade path is relatively straightforward and another form of Routing Engine hardware and software upgrade. However, there are three different and distinct Routing Engine configurations that must be taken into account when upgrading to the 64-bit Junos OS. This topic covers all three.
The In Service Software Upgrade (ISSU) procedure is not supported while upgrading from the 32-bit version of Junos OS to the 64-bit version of Junos OS. The upgrade process involves some downtime, so traffic will be affected.
 | Note: The 64-bit version of Junos OS is not supported on every Routing Engine. To determine whether your router and Routing Engine support a 64-bit version of Junos OS, see Supported Routing Engines by Chassis. |
Before you begin, you must have:
- A properly configured and functional router
- One or two Routing Engines installed that support the 64-bit Junos OS
- Decided to allow single Routing Engines systems to use either slot 0 or slot 1 as master or not (this decision will determine which upgrade path to follow for single Routing Engine systems)
When you upgrade a Routing Engine to the 64-bit Junos OS, you can support larger Routing Engine memory sizes. However, the exact procedure depends on whether there are one or two Routing Engines installed. For systems with a single Routing Engine, the procedure varies based on whether the master Routing Engine must always be in slot 0 or not.
To upgrade a system with two Routing Engines, refer to Figure 1 and perform the following steps:
Figure 1: Upgrading to the 64-bit Junos OS with Dual Routing Engines
- In the initial state, both Routing Engines are running the 32-bit Junos OS, and slot 0 has the master Routing Engine.
- Upgrade the slot 1 Routing Engine hardware and install
the 64-bit Junos OS.
For instructions on replacing a Routing Engine, see the hardware guide for your router.
- Switch the master Routing Engine from slot 0 to slot 1 (allow the 32-bit Junos OS to co-exist with the 64-bit Junos OS).
- Upgrade the slot 0 routing engine hardware and install the 64-bit Junos OS.
- Both Routing Engines now run the 64-bit Junos OS. Optionally, you can switch the master Routing Engine back to slot 0.
| Note: Mixing the 32-bit Junos OS with the 64-bit Junos OS is only supported temporarily during the upgrade process. Mixing the two operating systems is not supported for normal operations. |
Figure 2: Upgrading to the 64-bit Junos OS with a Single Routing Engine (Master in Either Slot)
To upgrade a system with a single Routing Engine, where the master Routing Engine can be in either slot 0 or slot 1, refer to Figure 1and perform the following steps:
- In the initial state, the slot 0 Routing Engine is running the 32-bit Junos OS and slot 1 is blank.
- Install the upgraded Routing Engine hardware in slot 1
and install the 64-bit Junos OS.
For instructions on installing a Routing Engine, see the hardware guide for your router.
- When the 64-bit Junos OS is configured properly, remove the slot 0 Routing Engine running the 32-bit Junos OS.
To upgrade a system with a single Routing Engine, where the master Routing Engine must be in slot 0, refer to Figure 3 and perform the following steps:
Figure 3: Upgrading to the 64-bit Junos OS with a Single Routing Engine (Master Must Be in Slot 0)
- In the initial state, the slot 0 Routing Engine is running the 32-bit Junos OS and slot 1 is blank.
- Install the slot 0 Routing Engine hardware in slot 1.
Install the upgraded Routing Engine hardware in slot 0 and install
the 64-bit Junos OS.
For instructions on installing a Routing Engine, see the hardware guide for your router.
- When the 64-bit Junos OS is configured properly, remove the slot 1 routing engine running the 32-bit Junos OS.
