I just wana ask several questions about NVRAM: 1.We all Know NVRAM will log the write IO,But I wonder if the log including the original Data?If NVRAM has to cache the original data,I think It's too small for the data stream incoming. 2.If the original data is cached in the RAM or NVRAM,does it mirror to the partner node?If not,when the partner node takeover the local node,then the original data cached in the RAM will lost?because the partner node can not get the original data(not log) by each other.
Recently we had this explaiined to us from NetAApp. When a write request comes it's cached in system memory, the system that requested the write operations is told is was completed, a copy of this write request is written to NVRAM then this is replicated to it's partner NVRAM. At some point the data is written to disk from the main memory. If a failure over takes place the partner is complete the write request. I hope this help.