Why is the “Hit Rate History" in “Cache Acceleration” 0%?
There are three possible reasons.
1) If the data volume is small, all of data will be in the memory’s cache. Although the memory cache is hit, it does not hit the SSD cache, making the displayed hit ratio relatively low or 0.
2) If the data is sequentially read, the system will not place this data into the cache to facilitate better cache usage (by default). To configure this option, go to "Storage Manager" > "Cache Acceleration" > "Cache Setting" > "Bypass Prefetch Data". This is enabled by default, indicating that cache data prefetch will not be performed during sequential reading.
3) The repetitive rate of the data is very low, and is not present in the cache. The cache will therefore not be hit.