Regarding the scenario of small I0 write cache in Huawei's distributed storage multi-level cache technology, which of the following order is correct? 1 Write to the WAL log area based on the SSD…

Regarding the scenario of small I0 write cache in Huawei's distributed storage multi-level cache technology, which of the following order is correct? 1 Write to the WAL log area based on the SSD slow disk, and return to the host to complete the write operation 2 When the memory write cache reaches a certain water level, the data starts to be flushed down 3 Data writing to RAM-based Write Cache 4 Small IOs will be written to the SSD cache of the node first, waiting to be aggregated into large IOs and then written to HDD