The key three circumstances from which you should protect a write cache are: power failure, cache device failure and server failure. Cache safety is especially important when caching writes. A write cache acknowledges the write before it is safely committed to hard disk. Caches built from shared storage systems will leverage the mirroring or RAID built into the storage system. With proper design, writes can be safely cached with proper design and both sides of the I/O equation can benefit from memory-based storage solutions.”]
Source: https://www.darkreading.com/database-security/3-ways-to-protect-cache-writes