Linux memory management: Real memory or Cached buffers?
I wanted to know more about how to look at a linux (Red Hat Enterrprise) in terms of memory ? Should you look at "real memory " free using top or free -m or should you pay attention to "CAched buffers"
For example lets take this output from "free -m"
bash-3.00$ free -m
total used free shared buffers cached
Mem: 15808 15130 677 0 113 6171
-/+ buffers/cache: 4845 10963
Swap: 2047 0 2047
So lets say when you do ps -ef you see ther are a few java process and combined memory usage is around 10Gigs. So question is
a) Where is the rest of the memory ? Was it used for cached buffers when copying over some big files?
b) Can I start say 2 more java process with 2Gig heap space and it will get memory from the "cached buffers"
Bottom line if you want a healthy system should you be worried if you dont have real memory but have a lot of cached buffers?