Home > Storage > PowerMax and VMAX > Storage Admin > Reliability, Availability, and Serviceability on PowerMax 2500 and 8500 Arrays > Vaulting
We vault to save all persistent data to the flash drives when the system is shutting down or going offline, then restore when the system reboots. The purpose of vaulting is to prevent data loss. During a vault, memory is saved locally (does not traverse fabric) and D@RE is incorporated at the drive level. As cache size has grown, the time required to move all cached data to a persistent state has also increased. Vaulting is designed to limit the time needed to power off the system if it needs to switch to a battery supply
Upon complete system power loss, or transitioning a system to an offline state, PowerMaxOS performs a vault of cache memory to dedicated NVMe SSD drives. The PMEM is already persistent (as the name implies) and does not need to be vaulted. The SSD drives use NVMe technology to safely store data in cache during the vaulting sequence. These NVME SSD vault drives plug into slots on the front of the node.