-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Thomas Guyot-Sionnest wrote: > On 22/08/08 10:46 AM, Edwin Zoeller wrote: >> We have recently installed Redhat AS4 throughout our network. I have >> installed various plugins from the Nagios Exchange site for Linux and >> all seems to be well, except for the check_ram command. I am running >> this on various servers with different configurations and all are giving >> the same results. Here is what I have on one of the servers: > >> check_ram -n -w 20MB -c 10MB ( the system has 8GB installed), results >> display 30MB free (am I doing this right?) > >> Other admins here are disputing the results and claim that Linux buffers >> all the memory and gives what it needs. I don't know for fact it this is >> true. I have also run top, free and ps -eo checking on memory size, all >> give back the same results as the Nagios plugin. Is this plugin with the >> option chosen giving real memory results or bogus results. > >> My question, in desperation, can anyone explain in very simple terms how >> Linux memory works? Also how are you monitoring memory, using what >> command and how it is configured etc. > > All unused memory gets buffered/cached eventually if your server is > doing I/0. I've seen very stable servers with 32GB get down to only a > few MBs free, but the picture is much better if you account the > buffered/cached memory which for most of it can be freed anytime if needed. > > For that reason you should add the buffer/cache memory to the total > (i.e. the "-/+ buffers/cache:" line of the "free" command). > > My check_memory script does that. it's written in Perl and uses the > Nagios::Plugin Perl module (available on CPAN). > > http://www.nagiosexchange.org/cgi-bin/page.cgi?g=1433.html;d=1
The whole point of this is that unused memory is wasted memory. So if you do not use RAM for aplications itself your system will find a good use for it to speed up the system by using it for buffers and cache. Hugo. - -- [EMAIL PROTECTED] http://hugo.vanderkooij.org/ PGP/GPG? Use: http://hugo.vanderkooij.org/0x58F19981.asc A: Yes. >Q: Are you sure? >>A: Because it reverses the logical flow of conversation. >>>Q: Why is top posting frowned upon? Bored? Click on http://spamornot.org/ and rate those images. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) iD8DBQFIr8bBBvzDRVjxmYERAlAZAKCWrQ+HVxx5c48bKP9QLjOp87+MLQCcCoR9 sf13K2ppzE5ncjEZ1xaGNro= =8xVk -----END PGP SIGNATURE----- ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Nagios-users mailing list Nagios-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nagios-users ::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. ::: Messages without supporting info will risk being sent to /dev/null