Hi Zerolimit,
It seems like Harvest is getting late responses from your OCUM system. What you can do is change the default timeout parameter in Harvest and seek help from support for the OCUM API response time.
You can manually edit netapp-worker to change the default timeout setting. This file is usually located in the folder /opt/netapp-harvest/. You can use vim or nano to edit the file.
On line 612 you should see this:
$out = $s->set_timeout('60');
Change 60 to 180, save and restart Harvest. If it doesn't help, try again by setting it to 300.