Starting in 13.x the linux kernel has increased swappiness, making it look like more RAM is in use. Well, that's because it is, and it's a good thing.
How to use this snippet:
Are you a fan of head-math?
Probably; Here is a challenge for you; look at the `free` output below and tell me what percentage of memory is used for each line of output (Mem:, -/+ buffers/cache:, Swap:)...Go!
Example `free` outupt.
total used freeshared buffers cached
Mem: 8199736 8091608 108128 105916 24532 392148
-/+ buffers/cache: 7674928 524808
Swap: 1023996 96020 927976
However let's pretend you're not a fan of head-math, or you simply like one-liners.
This is a simple one-liner to show you how much memory is actually used on the BIG-IP Linux Host system.
Pretty Memory Usage Output (In Percentage)
Straight-forward: "How much memory is each aspect of the Linux Host System using?"
Example Output (Percentages)
Mem Used: 98.6316
Used After Buffers: 6.83044
Swap Used: 9.37699
This output tells us that 98.6316 percent of RAM is used, however 91.80116 percent is just buffers/cache and is actually eligible to be used by any other service that needs it.
The takeaway here is that, though the memory used may appear to be high, that's actually a really good thing. It means that some data at some point was needed, and so it was cached in memory. It will now stay there until it is needed again or it gets pushed out by another process which needs that memory. Either way, this is a healthy system.