Is my data protected by the Battery Backup Unit (BBU) during a power outage?

All data in a subsystem’s controller cache is protected assuming you have both Batteries present and fully charged with at least 72 hours of hold time. Please reference the User Manual on “adaptive write cache” function.
                

In the event the battery becomes marginal and adaptive write cache feature is enabled (enabled by default) the controller firmware will switch the controller write cache to write thru to protect controller cache data.Physical disk cache is not protected. If this is a concern it is possible to turn off physical disk write caching from WebPAM, the CLI or the CLU. This is a global setting forall drives and it can be found in the Enclosure tab or menu.Turning off drive write caching will significantly reduce write performance.   Read performance will not be affected