MongoDB 3.0.2 Wired Tiger Cachesize GB Restrict Memory Use

  mongodb

Arguably mongodb 3.0.2 wt engine configuration cacheSizeGB should be able to limit the use of memory ah, however, we 2G memory machine configuration after this parameter is 1G, slowly memory can still be used to 80%. . .

Why is this? Our understanding of this parameter is wrong?

CacheSizeGB only limits the memory used by the storage engine but the memory used by the storage engine is less than the total memory used by mongodb