Any updates that you make to variables, including the date and time, in the control domain or in any guest domain persist across a reboot.
If you save a new logical domain configuration to the SP prior to performing a power cycle, the variable, date, and time updates are preserved across power cycles. So, each time you update a variable, the date or time, save a new configuration to the SP after you make the change.
Starting with the SPARC T4, SPARC M5, and SPARC S7 series servers, any updates you make to variables in the control domain are preserved automatically across a power cycle. On these servers, you do not need to save a configuration to the SP prior to a power cycle. On older-generation SPARC servers, only updates made at the OpenBoot prompt are automatically preserved.