The data cache contains the last read- or write-accessed pages of the data volumes. It is shared by all simultaneously active users.
The data cache is dimensioned dynamically, which means that you cannot directly influence its size. The required pages are taken from the I/O buffer cache. If the converter grows, the number of data cache pages is reduced accordingly.
The hit rate, that is the proportion of successful accesses in the total number of accesses to the data cache, is a crucial measure of performance. Successful access means that the required data was already available in the data cache when it was accessed.