I'm using nsclient++ to check our windows server and so far so good. However, for servers with large disks, the 10% threshold isn't cutting it. Ten percent is really 18G free and that's still a lot of available space. Is there a way to specify a hard value say "6G" instead of 10%?
5 Answers
You can set a fixed size in nsclient++ CheckDriveSize command, see http://nsclient.org/nscp/wiki/CheckDriveSize . That said, NTFS suffers from performance problems on partitions that are greater than 80% full so just keep that in mind.
You can always change the percentage. Some of our larger systems are tuned to alert at, e.g., 5% or 2%, depending on (a) total available space and (b) usage patterns.
As larsks said we also just adjust the percentage to fit the needs of the server. Although it's worth considering that if you're down to 10% on a drive, that means you've got it 90% full - you still might want to consider cleaning it or adding more storage. While 18 gigs free is a lot - you still may want to have ample time and warning to start considering what, if any, actions you may need to take soon.
Just keep in mind that filesystems do start to have performance issues as they fill up. XFS is probably the most notorious for this. So while 20% may seem high it is possible for it to cause some issues.
Also most ext* filesystems default to 5% reserved space. So it's possible to run into out of space issues before you actually fill up the drives.
FIY.
In 0.3.9 (not yet release BTW) "check_mk's magick" disk modifiers will be added so it can rescale the percentages between large and small drives (so you can use 80% but for very large drives this will be increased to a larger value).
// Michael Medin