@corona, thanks that was a relief. I logged a case with RHEL just in case and they told me the same thing you did but in totally incomprehensible terms
@mark, thanks for the vmstat syntax. I suppose cat /proc/meminfo provided me with more or less the same info
@murphy, I did check the link you provided but I got lost halfway thru I think I was just too stressed to figure it out yesterday!
Anyways, just in case someone comes across this thread and wants answers, following is the math concoction:
Code:
For example (Units are in megabytes):
# free -m
total used free shared buffers cached
Mem: 1000 900 100 0 350 350
-/+ buffers/cache: 200 800
In this example, as far as applications are concerned the system is using only 200MB of memory and has 800MB free and available for use if needed.
Note: in this example,
Total Physical Memory = 1000 M
Physically Used Memory = 900 M
Actual used memory = 200 M
buffers = 350 M
cached = 350 M
Physically Free Memory = 100 M
Memory free for Applications = 800 M
The items to note here are:
<Physically Used Memory> = <Actual used memory> + <buffers> + <cache> = 200 + 350 + 350 = 900 M
<Physically Free Memory> = <Total Physical Memory> - <Actual used memory> - <buffers> - <cache> = 1000 - 200 - 350 - 350 = 100 M
<Memory free for Applications> = <Total Physical Memory> - <Actual used memory> = 1000 - 200 = 800 M
<Memory used by Applications> = <Physically Used Memory> - <buffers> - <cache> = 900 - 350 - 350 = 200 M
Hy, I've an 486 dx2 laptop an I want to run unix on it, the problem is it has only 4 megabytes of ram, so my question is; does anybody know an unix based OS which runs with only 4 mb?
thanx (7 Replies)
Hi,
I am seeing very high kernel usage and very high load averages on my system (Although we are not loading much data to our database). Here is the output of top...does anyone know what i should be looking at?
Thanks,
Lorraine
last pid: 13144; load averages: 22.32, 19.81, 16.78 ... (4 Replies)
Hi All,
In my application malloc is returning NULL even though there is sufficient amount of free memory is available but swap memory is low.
Is this possible that, if free memory is high & swap memory is low, malloc will not be able to allocate memory & return NULL ?:)
Kindly look into... (5 Replies)
on the file Ftp'd from the mainframe ,do we have any UNIX command to replace mainframe low and values to space or null.
i tried using tr and it doesn't work ...
Thanks (1 Reply)
Is it possible to have a bash script pick the highest and lowest values of four variables? I've been googling for this but haven't come up with anything. I have a script that assigns variables ($c0, $c1, $c2, and $c3) based on the coretemps from grep/sed statements of sensors. I'd like to also... (5 Replies)
Hi guys,
i have a question about spliting a binary file into 2 chunks.
First chunk with all high bytes and the second one with all low bytes.
What unix tools can i use? And how can this be performed?
I looked in manpages of split and dd but this does not help.
Thanks (2 Replies)
I've got a domain running on a few boards of a 25k. I'm seeing very high kernel cpu usage in top and cant' quite explain it. System runs a large number of smallish Oracle 10g2 databases (30), used mainly for development.
load average: 36.63, 36.68, 37.42
2489 processes: 2452 sleeping, 21... (0 Replies)
Need some clarification on this....
1. how are kernel/ user spaces and high/low memory related?
2. What do they all mean when i have the kernel command line as:
"console=ttyS0,115200 root=/dev/sda2 rw mem=exactmap memmap=1M@0 memmap=96M@1M irqpoll"
or
2. what do mem and memmap mean in... (3 Replies)
Hello All
I have a system running AIX 61 shared uncapped partition (with 11 physical processors, 24 Virtual 72GB of Memory) .
The output from NMON, vmstat show a high run queue (60+) for continous periods of time intervals, but NO paging, relatively low I/o (6000) , CPU % is 40, Low network.... (9 Replies)
Discussion started by: IL-Malti
9 Replies
LEARN ABOUT PLAN9
free
FREE(1) User Commands FREE(1)NAME
free - Display amount of free and used memory in the system
SYNOPSIS
free [options]
DESCRIPTION
free displays the total amount of free and used physical and swap memory in the system, as well as the buffers and caches used by the ker-
nel. The information is gathered by parsing /proc/meminfo. The displayed columns are:
total Total installed memory (MemTotal and SwapTotal in /proc/meminfo)
used Used memory (calculated as total - free - buffers - cache)
free Unused memory (MemFree and SwapFree in /proc/meminfo)
shared Memory used (mostly) by tmpfs (Shmem in /proc/meminfo)
buffers
Memory used by kernel buffers (Buffers in /proc/meminfo)
cache Memory used by the page cache and slabs (Cached and SReclaimable in /proc/meminfo)
buff/cache
Sum of buffers and cache
available
Estimation of how much memory is available for starting new applications, without swapping. Unlike the data provided by the cache or
free fields, this field takes into account page cache and also that not all reclaimable memory slabs will be reclaimed due to items
being in use (MemAvailable in /proc/meminfo, available on kernels 3.14, emulated on kernels 2.6.27+, otherwise the same as free)
OPTIONS -b, --bytes
Display the amount of memory in bytes.
-k, --kibi
Display the amount of memory in kibibytes. This is the default.
-m, --mebi
Display the amount of memory in mebibytes.
-g, --gibi
Display the amount of memory in gibibytes.
--tebi Display the amount of memory in tebibytes.
--pebi Display the amount of memory in pebibytes.
--kilo Display the amount of memory in kilobytes. Implies --si.
--mega Display the amount of memory in megabytes. Implies --si.
--giga Display the amount of memory in gigabytes. Implies --si.
--tera Display the amount of memory in terabytes. Implies --si.
--peta Display the amount of memory in petabytes. Implies --si.
-h, --human
Show all output fields automatically scaled to shortest three digit unit and display the units of print out. Following units are
used.
B = bytes
K = kibibyte
M = mebibyte
G = gibibyte
T = tebibyte
P = pebibyte
If unit is missing, and you have exbibyte of RAM or swap, the number is in tebibytes and columns might not be aligned with header.
-w, --wide
Switch to the wide mode. The wide mode produces lines longer than 80 characters. In this mode buffers and cache are reported in two
separate columns.
-c, --count count
Display the result count times. Requires the -s option.
-l, --lohi
Show detailed low and high memory statistics.
-s, --seconds delay
Continuously display the result delay seconds apart. You may actually specify any floating point number for delay using either .
or , for decimal point. usleep(3) is used for microsecond resolution delay times.
--si Use kilo, mega, giga etc (power of 1000) instead of kibi, mebi, gibi (power of 1024).
-t, --total
Display a line showing the column totals.
--help Print help.
-V, --version
Display version information.
FILES
/proc/meminfo
memory information
BUGS
The value for the shared column is not available from kernels before 2.6.32 and is displayed as zero.
Please send bug reports to
<procps@freelists.org>
SEE ALSO ps(1), slabtop(1), top(1), vmstat(8).
procps-ng 2016-06-03 FREE(1)
04-16-2012
SOLVED
