SNMP based template for memory / swap usage on a Unix host

fmangeant · Post by **fmangeant** » Tue Feb 05, 2008 9:37 am

Edit : these templates now work with Cacti 0.8.7b, thanks to phalek

Hi

here are some templates for memory & swap under Unix; they use SNMP queries only.

The ucd/net - Memory Usage (Linux) graph template works only with Linux hosts, but the ucd/net - Memory Usage and ucd/net - Swap Usage graph templates work with any Unix system running Net-SNMP (including Linux).

These templates were exported from a Cacti 0.8.7a installation, so you need at least this version.

Beware when importing these templates, I'm using "large" RRA definitions...

Findarato · Post by **Findarato** » Wed Feb 06, 2008 3:03 pm

Having a little issue with your graphs, using 8.7a

as you can see the graphs are well not exactly working correctly. I am not exactly sure what the issue is.

The totals are correct for both graphs, just the rest are not.

fmangeant · Post by **fmangeant** » Thu Feb 07, 2008 3:17 am

Hi

did you apply the first patch available here ?

Findarato · Post by **Findarato** » Thu Feb 07, 2008 10:44 am

I had not applied those patches. After applying them the Pink graph started working, but not the more in depth Linux one. All the hosts being graphed this way are running Fedora 7/8 and the newest Net-SNMP.

I have attached what the graph looks like ATM, that I am having issue with. I added the graph of one of our servers running F7, the one from "Auto1" is running F8 if that matters, both have the same version of NET-SNMP.

agentc0re · Post by **agentc0re** » Sat Feb 16, 2008 4:28 pm

Hi, first i would like to thank you for making these graphs!

Awesome work.
I am having some issues with the linux one though. I am using latest 8.7b.
it imports just fine and creates the RRD fine as well. However the used memory shows a negative number. when i look in Graph Templates and click on ucd/net - memory usage (linux), the first 5 Items for Memory used have NO TASK.
I have searched the forums for a resolution but found that everyone got it fixed for patches for 8.7a but im using b which should have those fixes already.

What are your suggestions?

Code: Select all

root@yoda:~# snmpwalk -v 1 -c public localhost memory

UCD-SNMP-MIB::memIndex.0 = INTEGER: 0

UCD-SNMP-MIB::memErrorName.0 = STRING: swap

UCD-SNMP-MIB::memTotalSwap.0 = INTEGER: 1831400 kB

UCD-SNMP-MIB::memAvailSwap.0 = INTEGER: 1831400 kB

UCD-SNMP-MIB::memTotalReal.0 = INTEGER: 2070608 kB

UCD-SNMP-MIB::memAvailReal.0 = INTEGER: 1543512 kB

UCD-SNMP-MIB::memTotalFree.0 = INTEGER: 3374912 kB

UCD-SNMP-MIB::memMinimumSwap.0 = INTEGER: 16000 kB

UCD-SNMP-MIB::memShared.0 = INTEGER: 0 kB

UCD-SNMP-MIB::memBuffer.0 = INTEGER: 240 kB

UCD-SNMP-MIB::memCached.0 = INTEGER: 407188 kB

UCD-SNMP-MIB::memSwapError.0 = INTEGER: noError(0)

UCD-SNMP-MIB::memSwapErrorMsg.0 = STRING:

root@yoda:~# snmpwalk -v 2c -c public localhost memory

UCD-SNMP-MIB::memIndex.0 = INTEGER: 0

UCD-SNMP-MIB::memErrorName.0 = STRING: swap

UCD-SNMP-MIB::memTotalSwap.0 = INTEGER: 1831400 kB

UCD-SNMP-MIB::memAvailSwap.0 = INTEGER: 1831400 kB

UCD-SNMP-MIB::memTotalReal.0 = INTEGER: 2070608 kB

UCD-SNMP-MIB::memAvailReal.0 = INTEGER: 1526740 kB

UCD-SNMP-MIB::memTotalFree.0 = INTEGER: 3358140 kB

UCD-SNMP-MIB::memMinimumSwap.0 = INTEGER: 16000 kB

UCD-SNMP-MIB::memShared.0 = INTEGER: 0 kB

UCD-SNMP-MIB::memBuffer.0 = INTEGER: 240 kB

UCD-SNMP-MIB::memCached.0 = INTEGER: 407220 kB

UCD-SNMP-MIB::memSwapError.0 = INTEGER: noError(0)

UCD-SNMP-MIB::memSwapErrorMsg.0 = STRING:

fmangeant · Post by **fmangeant** » Sun Feb 17, 2008 3:28 am

I've not tried this template on 0.8.7b, will do tomorrow.

fmangeant · Post by **fmangeant** » Tue Feb 19, 2008 3:26 am

You're riight, it does not work with 0.8.7b

I've opened bug #1187

agentc0re · Post by **agentc0re** » Tue Feb 19, 2008 8:45 am

Thank you for checking into it and opening the bug!

phalek · Post by **phalek** » Fri Mar 28, 2008 6:30 am

There's a simple solution to this, the CDEFs for the graphs are wrong. Seems like the graph now has some more RRD files (MAX in addition to AVERAGE) and therefore the calculation for the CDEFs are wrong ...

To fix this do the following:

Go to Management -> Graph Management -> CDEFs
Select the Memory Used CDEF
It should display something like "cdef=d,c,-,b,-,a,-,1024,*"
you'll need to change this, so it states something like: "cdef=g,e,-,c,-,a,-,1024,*"

In order to get the correct function, you need to look at the graph properties of the memory graph. There are some lines displaying the following:

Code: Select all

DEF:a="/home/cacti-087b/rra/cachebox_mem_buffers_49.rrd":mem_buffers:AVERAGE \
DEF:b="/home/cacti-087b/rra/cachebox_mem_buffers_49.rrd":mem_buffers:MAX \
DEF:c="/home/cacti-087b/rra/cachebox_mem_cache_50.rrd":mem_cache:AVERAGE \
DEF:d="/home/cacti-087b/rra/cachebox_mem_cache_50.rrd":mem_cache:MAX \
DEF:e="/home/cacti-087b/rra/cachebox_mem_free_51.rrd":mem_free:AVERAGE \
DEF:f="/home/cacti-087b/rra/cachebox_mem_free_51.rrd":mem_free:MAX \
DEF:g="/home/cacti-087b/rra/cachebox_mem_total_52.rrd":mem_total:AVERAGE \
DEF:h="/home/cacti-087b/rra/cachebox_mem_total_52.rrd":mem_total:MAX \
DEF:i="/home/cacti-087b/rra/cachebox_swap_free_53.rrd":swap_free:AVERAGE \
DEF:j="/home/cacti-087b/rra/cachebox_swap_free_53.rrd":swap_free:MAX \
DEF:ba="/home/cacti-087b/rra/cachebox_swap_total_54.rrd":swap_total:AVERAGE \
DEF:bb="/home/cacti-087b/rra/cachebox_swap_total_54.rrd":swap_total:MAX \
CDEF:cdefa=a,0,* \
CDEF:cdefb=g,e,-,c,-,a,-,1024,* \

So the CDEF needs to state the following: mem_used(average) = ( mem_total(average) - mem_free(average) - mem_cache(average) - mem_buffers(average) ) * 1024

phalek · Post by **phalek** » Fri Mar 28, 2008 6:33 am

BTW, the swap info has the same problem, the CDEF for swap_used is using/refering to the wrong rrd files ....

phalek · Post by **phalek** » Fri Mar 28, 2008 6:36 am

One addition, after changing the CDEFs for the graph cacti calculates the mem_used only after it got the latest values for the other sources. It's N/A until then and the graph will not show the mem_used.

To fix this you'll need to add an invisible area right at the top of the graph template (see screenshots)

fmangeant · Post by **fmangeant** » Wed Apr 02, 2008 9:43 am

Many many thanks for finding this "bug"

I've uploaded corrected versions of the templates (tested on a clean 0.8.7b + PIA 2.1 installation).

agentc0re · Post by **agentc0re** » Tue Apr 08, 2008 1:12 pm

I just downloaded the updated files. They're the ones still listed up at the top of this thread, right?

Anyways, before importing them i deleted all my rra's and the templates, data sources the whole shebang. However, when i reupload the template and try to use it, i'm still have the same issue where the memory used is a negative #.

I probably didn't do everything i needed or possibly downloaded the wrong files. could you help point me in the right direction? Thanks!

phalek · Post by **phalek** » Tue Apr 08, 2008 1:40 pm

Just go and check the graph properties for the rras and the CDEF function if that is correct (see the formular in one of my earlier posts) . Or simply paste it here (in code tags

) so we can have a look at it

agentc0re · Post by **agentc0re** » Tue Apr 08, 2008 2:27 pm

phalek, i appreciate you helping me out with this

Here's the info.

Code: Select all

/usr/bin/rrdtool graph - \
--imgformat=PNG \
--start=1207592838 \
--end=1207679238 \
--title="Bobafett - Memory Usage" \
--base=1024 \
--height=120 \
--width=500 \
--alt-autoscale-max \
--lower-limit=0 \
COMMENT:"From 2008/04/07 12\:27\:18 To 2008/04/08 12\:27\:18\c" \
COMMENT:"  \n" \
--vertical-label="bytes" \
--slope-mode \
--font TITLE:12: \
--font AXIS:8: \
--font LEGEND:10: \
--font UNIT:8: \
DEF:a="/opt/cacti/rra/bobafett_mem_buffers_349.rrd":mem_buffers:AVERAGE \
DEF:b="/opt/cacti/rra/bobafett_mem_buffers_349.rrd":mem_buffers:LAST \
DEF:c="/opt/cacti/rra/bobafett_mem_buffers_349.rrd":mem_buffers:MIN \
DEF:d="/opt/cacti/rra/bobafett_mem_buffers_349.rrd":mem_buffers:MAX \
DEF:e="/opt/cacti/rra/bobafett_mem_cache_350.rrd":mem_cache:AVERAGE \
DEF:f="/opt/cacti/rra/bobafett_mem_cache_350.rrd":mem_cache:LAST \
DEF:g="/opt/cacti/rra/bobafett_mem_cache_350.rrd":mem_cache:MIN \
DEF:h="/opt/cacti/rra/bobafett_mem_cache_350.rrd":mem_cache:MAX \
DEF:i="/opt/cacti/rra/bobafett_mem_free_351.rrd":mem_free:AVERAGE \
DEF:j="/opt/cacti/rra/bobafett_mem_free_351.rrd":mem_free:LAST \
DEF:ba="/opt/cacti/rra/bobafett_mem_free_351.rrd":mem_free:MIN \
DEF:bb="/opt/cacti/rra/bobafett_mem_free_351.rrd":mem_free:MAX \
DEF:bc="/opt/cacti/rra/bobafett_mem_total_352.rrd":mem_total:AVERAGE \
DEF:bd="/opt/cacti/rra/bobafett_mem_total_352.rrd":mem_total:MAX \
CDEF:cdefa=g,e,-,c,-,a,-,1024,* \
CDEF:cdeff=a,1024,* \
CDEF:cdefg=b,1024,* \
CDEF:cdefi=c,1024,* \
CDEF:cdefj=d,1024,* \
CDEF:cdefba=e,1024,* \
CDEF:cdefbb=f,1024,* \
CDEF:cdefbd=g,1024,* \
CDEF:cdefbe=h,1024,* \
CDEF:cdefbf=i,1024,* \
CDEF:cdefbg=j,1024,* \
CDEF:cdefbi=ba,1024,* \
CDEF:cdefbj=bb,1024,* \
CDEF:cdefca=bc,1024,* \
CDEF:cdefcb=bd,1024,* \
AREA:cdefa#FFF200FF:"Memory Used"  \
GPRINT:cdefa:LAST:"   Current\:%8.2lf %s"  \
GPRINT:cdefa:AVERAGE:"Average\:%8.2lf %s"  \
GPRINT:cdefa:MIN:"Min\:%8.2lf %s"  \
GPRINT:cdefa:MAX:"Max\:%8.2lf %s\n"  \
AREA:cdeff#6EA100FF:"Memory Buffers":STACK \
GPRINT:cdefg:LAST:"Current\:%8.2lf %s"  \
GPRINT:cdeff:AVERAGE:"Average\:%8.2lf %s"  \
GPRINT:cdefi:MIN:"Min\:%8.2lf %s"  \
GPRINT:cdefj:MAX:"Max\:%8.2lf %s\n"  \
AREA:cdefba#942D0CFF:"Memory Cached":STACK \
GPRINT:cdefbb:LAST:" Current\:%8.2lf %s"  \
GPRINT:cdefba:AVERAGE:"Average\:%8.2lf %s"  \
GPRINT:cdefbd:MIN:"Min\:%8.2lf %s"  \
GPRINT:cdefbe:MAX:"Max\:%8.2lf %s\n"  \
AREA:cdefbf#12B3B5FF:"Memory Free":STACK \
GPRINT:cdefbg:LAST:"   Current\:%8.2lf %s"  \
GPRINT:cdefbf:AVERAGE:"Average\:%8.2lf %s"  \
GPRINT:cdefbi:MIN:"Min\:%8.2lf %s"  \
GPRINT:cdefbj:MAX:"Max\:%8.2lf %s\n"  \
LINE1:cdefca#000000FF:"Memory Total"  \
GPRINT:cdefcb:MAX:"  Current\:%8.2lf %s"

I think i understand why. The cdef is subtracting from itself in the equation. However, i'm not sure how to change that.

SNMP based template for memory / swap usage on a Unix host

SNMP based template for memory / swap usage on a Unix host

Who is online