I monitor 1 vSphere 5.1 site directly from server, 2 vSphere 5.1 sites via proxies and 10 standalone ESXi 5.1. There are over 250 VMs and over 20 hosts.

In period with ~1 hours i see that count of unsupported items for vmware hosts increasing very much. This looks in 5-10 minutes and then decrease back. When it increasing, CURL error shown in sever log like that: "Item beaCannot set cURL option [10015]: Timeout was reached" and simply "Timeout was reached". Example:

"17185:20140129:143255.360 item [5005be02-9556-753b-0627-e91dd850ba2c:vmware.vm.vfs.fs.size[{$URL},{HOST.HOST},/home,total]] became not supported: a timeout was reached"

My server works on CentOS installed in VMWare VM that running on BL460c G8 server. VM have 10GB of RAM, 2 vCPU and storage on SAN SAS10K disks. DB is MySQL, running on the same server. DB is optimized for innodb_file_per_table

Proxies runs on the same hardware configuration, but have 2GB of RAM.

I don't see that CPU, memory or disk I/O overloaded on server or proxies when error appears.

This error appears only with VMWare hosts, vcenters and vms.