ES_DIRECT_SIZE doesn't work

I am setting both ES_DIRECT_SIZE: 2048 and XX:MaxDirectMemorySize=2048m.

But still ES working set in windows goes beyond 10G.

I am doing simple searches against a 26GB index.

Working set and heap size are different things. I don't believe you can control the former.

Seems like using simplefs is the only way to go about it.

How bad is the performance with simplefs compared to MMap on windows ?