The raid.timeout option controls how long a storage system runs after a RAID group goes into degraded mode or the NVRAM battery malfunctions or loses power. You can change the value of this option, but you should understand the implications of doing so.
The purpose for the system shutdown is to avoid data loss, which can happen if an additional disk failure occurs in a RAID group that is already running in degraded mode, or if a stand-alone system encounters a catastrophic error and has to shut down without NVRAM. You can extend the number of hours the system operates in these conditions by increasing the value of this option (the default value is 24). You can even disable the shutdown by setting the option to 0, but the longer the system operates with one or both of these conditions, the greater the chance of incurring data loss.