how to find out free memory?

Linux and Unix-Like Red Hat
1

hi, I have done the below, but am confused as to how much memory is "free"

please help

thanks

$ free
             total       used       free     shared    buffers     cached
Mem:     132033488   48827536   83205952          0    1007696   45404632
-/+ buffers/cache:    2415208  129618280
Swap:    134217720          0  134217720
2

The numbers under the free column

first number: free memory
buffers : can be freed quickly
swap : virtual memory

Total free memory = free memory + unused swap. When memory gets short the OS will
release some cache memory as well.

Your system is in great shape memory-wise. I don't see a problem.

3

thanks for the reply.

ok, so I am using 48G and have 83G free. But what does the buffers and cache columns tell me?

Also, the row:

-/+ buffers/cache: 2415208 129618280

is confusing me

thanks

4

Using

free -m

with MB formatting

5

sorry, im not sure how this answers my question

elaborate?

6

From the free man page:

This answers your question - free thinks buffer memory is really free memory. Which is what I explained above.

Free means it is not absolutely required by an active process. The kernel uses 'extra' memory to facilitate operations - like I/O. Those are the buffers in question. It is kind of like luxury uptake of an unrequired resource, if that makes more sense to you.

What are you trying to figure out?

7

thanks jim, i think i get it now, if not, i will post again

8

also see:

vmstat -sa -S M | grep memory