Memory won't released

[Prashan_Attanay]

Hi Mates,

Memory is getting increase when we have peak days which is fine, but after peak hours are over still memory is same, it won't decrease the memory. What is cause for that ? 

At the same in peak hours cpu get high then it decrease after peak hours are over

[Timothy_Hall]

The memory consumption displayed by the SmartView Monitor does not distinguish between memory being utilized for code execution vs. memory used for buffering/caching of disk operations.  Memory allocated for buffering/caching can be freed at a moment's notice if more memory is required for code execution.  Run "free -m" on the gateway, the "-/+ buffers/cache" line of the output will show you the true amount of memory used for code execution independent from buffering/caching, and how much memory is free to be allocated for code execution if necessary.

--
My Book "Max Power: Check Point Firewall Performance Optimization"
Second Edition Coming Soon

[Prashan_Attanay]

Thank you Tim,

This is output of Free -m 

free -m
            total used free shared buffers cached
Mem: 3948 3240 708 0 269 803
-/+ buffers/cache: 2166 1782
Swap: 10268 0 10267

and I notice there is bit difference between used memory in "free -m" and Actual Real memory  in "cpstat -f memory os"

cpstat -f memory os

Total Virtual Memory (Bytes): 14907256832
Active Virtual Memory (Bytes): 2276896768
Total Real Memory (Bytes): 4140376064
Active Real Memory (Bytes): 2276290560
Free Real Memory (Bytes): 1864085504
Memory Swaps/Sec: -
Memory To Disk Transfers/Sec: -

So what should worry more free -m output or cpstat -f memory os ?

[Timothy_Hall]

I always prefer the output of free -m.  Your firewall has 4GB of RAM (if you actually have more physical RAM than that make sure Gaia is set for 64-bit mode) and roughly 2.1GB (2166) is used for code execution with roughly 1.8GB (1782) free.  The middle number on the "Swap" line (0) indicates that the firewall is not tapping into swap space at all.  Bottom line is your firewall is just fine from a memory perspective.

--
My Book "Max Power: Check Point Firewall Performance Optimization"
Second Edition Coming Soon

[Prashan_Attanay]

Tim one more thing to clarify, as i see in "free -m" free memory is 708. Less than 20% of free memory, how is it fine ? Do we need to upgrade memory ?

[Timothy_Hall]

The 708 number is available memory that is not in use at all, either by code execution or buffering/caching.  Based on your output it is derived from this: 3948 - (2166 + 269 + 803) = 710 which is slightly off from 708 due to rounding.  1072 (~1GB) is currently allocated for buffering/caching and can be repurposed for code execution at any time if needed.   So the real free memory available is 1782; as such you do not need more memory on your firewall.  Adding more memory to just increase possible buffering/caching is not really worth it on a firewall.

--
My Book "Max Power: Check Point Firewall Performance Optimization"
Second Edition Coming Soon

[Prashan_Attanay]

Thank you very much Tim

Is there any method to clear Bufferes/Cache memory ?

[Timothy_Hall]

Other than rebooting, no.  You wouldn't want to clear it anyway since buffering/caching helps optimize access to files on the hard drive which is many orders of magnitude slower than having the disk data available in RAM.  The memory allocated for buffering/caching will be automatically re-allocated for code execution if necessary by Gaia, you don't need to do anything.

--
My Book "Max Power: Check Point Firewall Performance Optimization"
Second Edition Coming Soon

[EdesLC]

Nice documents about high memory consumption:

sk99547: Should I be concerened with the "High memory usage" alarms? | 

sk99593: High and low memory explanation |