We have database servers that are allocated a lot of RAM in VMware so that we can try to prevent having to go to disk as much. However, in the VMware vsphere resource allocation tab, we see that the consumed memory is normal, but the "active memory" is much lower. For example, we have one database server that is allocated 72GB RAM, SQL min/max is using 66GB (I confirmed target/total SQL RAM is indeed 66GB), but "active memory" is around 30GB with spikes of 50GB. Note that shared memory is almost nothing and there is no ballooning/compressing/swapping going on. Why is SQL and the buffer cache of SQL so large, but VMware says it is using much less memory? Can we lower the memory around 50GB without causing a performance hit?