there is many plugins or agents to use. NSClient++ has made very good development in release months with this plus other checks. One item I have seen to become very handy in recent versions is the ability to specific remain space left instead of a percentage remaining. when using big disks, 1% can be gigs of data left so thresholds and alerting becomes unreliable.
take a look here for 4.2.93
http://nsclient.org/nscp/downloads
install the client, and enable check_nrpe. once installed, open the nsclient.ini and nsclient-sample.ini
read the documentation too
http://nsclient.org/nscp/wiki
either allow args to execute with cmd or hard code them as an alias. (don't forget to stop and start the service to apply saved ini file configuration)
example from nagios server...
cd /usr/local/nagios/libexec/
./check_nrpe -u -H SERVERNAME -t 30 -c CheckDriveSize -a Drive=C: MinWarnFree=2G MinCritFree=26648M ShowAll=long
OK: C:: Total: 39.9GB - Used: 12.965GB - Free: 26.935GB
|'C: free'=26GB;2;26;0;39 'C: free %'=67%;5;65;0;100
(notice this uses the size of free space remaining)
./check_nrpe -u -H SERVERNAME -t 30 -c CheckDriveSize -a Drive=C: MinWarnFree=2% MinCritFree=1% ShowAll
OK: C:: Total: 39.9GB - Used: 12.965GB - Free: 26.935GB
|'C: free'=26GB;0;0;0;39 'C: free %'=67%;1;0;0;100
(notice this uses the percent of free space remaining)
For performance data, plugins or executed checks use the pipe '|' to tell nagios that everything pass this is perfdata. Pretty simple when scripting or creating one from scratch. in the above two examples, nsclient produces the perfdata after pipe so you will trend and graph this data for historical purposes and capacity planning.
Of course, wmi and snmp can do this too, however up until recent nsclient versions, this ability to define a hard code of remaining space hasn't been there from all different types of checks. so if you have big volumes that are getting full, but the percentage of space to actually space is not a proper threshold, go with this latest 4.2.93 client install and start creating disk checks this way.
the only down fall is that XI doesn't have a dedicated check_nrpe for windows wizard yet as this is the main agent for linux, but thats not to stay that you can't create the templates for these checks with the windows wizard then go to the ccm, and change the check cmd and args there... the wizard can still do the under the hood configuration, like check intervals, alerting, service/host groups configs etc. use your nagios server to test or the ccm to test your checks, then apply configuration and your on your way.
Cheers,