Configuration Guide User guide
106 FastIron Configuration Guide
53-1002494-02
Hitless management on the FSX 800 and FSX 1600
Hitless OS upgrade considerations
Consider the following when using the hitless OS upgrade feature:
• Hitless OS upgrade allows for upgrading the software in a system between two releases of the
OS that support this functionality and have compatible data structures. A hitless O/S
downgrade may also be supported if the current and target code releases have compatible
data structures. From time to time it may be necessary, when enhancing the software or
adding new features, to change or add data structures that may cause some releases to be
incompatible. In such cases, an upgrade or downgrade will not be hitless, and the software will
use the regular Brocade upgrade process - relying on fast reboot.
• For a description of how this feature impacts major system functions, refer to Table 18 on
page 99.
• You must have both active and standby management modules installed to use this feature.
• Hitless OS upgrade is supported in software release FSX 05.0.00 or higher, with boot image
FSX 05.0.00 or higher. In general, it is supported with patch upgrades, for example, when
upgrading from release 07.0.01a to 07.0.01b. It is not supported during major release
upgrades, for example when upgrading from release 07.0.00 to 07.1.00.
• This feature can be used to upgrade an image to a higher or lower compatible version of the
software. However, if hitless upgrade to a particular software version is not supported, the
software upgrade must be performed through a fast reload of the system.
• Hitless OS upgrade between different types of software images is not supported. For example,
hitless OS upgrade is supported when upgrading the Layer 2 image to another Layer 2 image.
It is not supported when upgrading the Layer 2 image to a Layer 3 image, or the base Layer 3
image to a full Layer 3 image, and so on.
• Hitless OS upgrade should be performed locally, since remote connectivity will be lost during
the upgrade. During a reload, HTTP, SSH, Telnet, SNMP, and ping sessions will be dropped.
• The active management module switches from the initial active management module to the
standby management module during the hitless upgrade process. Therefore, a connection to
the console interface on both management modules is required.
• Upon being reset, any traffic going through the ports on the management module will be
interrupted. Once the management module is up and running, it will be able to send and
receive packets, even before the hitless upgrade process is complete.
• The running configuration is not allowed to be changed any time during the hitless upgrade
process.
• System-max configuration changes require a system reload. System-max configuration
changes do not take effect by the hitless upgrade. Even if a system-max parameter is changed
and saved in the startup configuration, the FastIron switch will revert to the default system-max
value upon a hitless software upgrade. The new system-max value will only take effect after a
regular system reload.
• Other commands requiring a software reload, such as CAM mode changes, also do not take
effect upon hitless upgrade and require a system reload before being placed in effect.