Hi,
please check notes
Note 1173395 - FAQ: SAP MaxDB and liveCache configuration
Note 1139904 - FAQ: SAP MaxDB/liveCache database parameters
the old name for CacheMemorySize was cache_size.
"When using the SAP liveCache technology, it should be possible to hold all data that is to be processed in the IO buffer cache."
That means, you should have a CacheMemorySize of the size of your (filled) LiveCache database.
So if your LiveCache database is filled with 10 Gb of data, your CacheMemorySize should be 10 GB, at least, too.
Best regards
Christian