Upgrading Stack Software

Context

Two methods are available to upgrade stack software: traditional upgrade and smooth upgrade. Table 1 compares the two upgrade methods.

**Table 1** Comparison of traditional and smooth upgrade methods
Upgrade Method	Command	Application Scenario	Master Switch After the Upgrade
Traditional upgrade	reboot	All member switches in the stack must restart during a traditional upgrade. This upgrade method causes service interruption for a relatively long period of time and is appropriate for use in scenarios insensitive to the service interruption time.	The switch with a high stack priority becomes the master switch. If switches have the same priority, the switch with a small MAC address becomes the master switch.
Smooth upgrade	upgrade backup-area slot slot-id to slot-id upgrade start	Member switches in a stack can be divided into an active area and a backup area that back up each other. Member switches in the two areas are upgraded in turn. During the upgrade of an area, traffic is transmitted through the other area, minimizing the impact of the upgrade on services. This upgrade method is appropriate for use in scenarios sensitive to the service interruption time. The stack and networking must meet the following requirements: The uplinks and downlinks work in redundancy mode. The system software for the next startup supports the smooth upgrade function. Member switches in the stack are running the same system software, with the same software package name, version, and path. Member switches in the stack all have the same system software for the next startup, with the same software package name, version, and path.	After the upgrade, the master switch must be located in the backup area.

Procedure

Traditional upgrade
1. Upload system software to the master switch in the stack. For details about how to upload files, see File Management in the S2720, S5700, and S6700 V200R019C10 Configuration Guide - Basic Configuration.
2. Run the startup system-software system-file all command to set the next startup software for all member switches in the stack.
3. Run the reboot command to upgrade the stack by restarting the entire system.
Smooth upgrade
1. Upload system software to all the member switches in the stack. Ensure that all member switches have the same system software, with the same software package name, version, and path. For details about how to upload files, see File Management in the S2720, S5700, and S6700 V200R019C10 Configuration Guide - Basic Configuration.
2. Run the startup system-software system-file all command to set the next startup software for all member switches in the stack.
3. Run the system-view command to enter the system view.
4. Run the upgrade backup-area slot slot-id to slot-id command to define the active and backup areas for a smooth upgrade.
  The member switches with stack IDs in the specified range join the backup area, and the other member switches automatically join the active area.
  Follow these rules to define the active and backup areas in a stack:
  The active and backup areas cannot have the same member switch, and both areas must have at least one member switch.
  The backup area cannot contain the master switch of the stack.
  Member switches in each area must be directly connected.
  Member switches in the active and backup areas form the entire stack.
5. (Optional) Run the display upgrade area command to check whether the configured areas meet the requirements of the current stack topology.
  If the stack topology changes after the areas are configured, the smooth upgrade will fail. To avoid this problem, check the area configuration before starting a smooth upgrade. If the areas fail the check, define the active and backup areas correctly according to the current stack topology.
6. Run the upgrade start command to enable smooth upgrade.
7. (Optional) Run the display upgrade state [ slot slot-id ] command to check the smooth upgrade status.