You may see this error in your agent logs accompanied by the agent hanging, thereby triggering no data received alerts.
This article is for our v1 agent and will soon be deprecated.
2012-03-02 00:10:57,107 - main - ERROR - getDiskUsage: df -k exception = Traceback (most recent call last):
File "/usr/bin/sd-agent/checks.py", line 421, in getDiskUsage
proc = subprocess.Popen(['df', '-k'], stdout=subprocess.PIPE, close_fds=True) # -k option uses 1024 byte blocks so we can calculate into MB
File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
File "/usr/lib/python2.7/subprocess.py", line 1133, in _execute_child
self.pid = os.fork()
OSError: [Errno 11] Resource temporarily unavailable
This is usually caused by a problem with one of your attached storage devices, most commonly a network attached storage system such as NFS. The agent uses several OS commands to get stats about disk usage and i/o stats and these commands will hang and wait for slow devices. As a result, the agent will also hang until they return.