Hi, I suspect you will be well advised to use the tool, "smartctl" which is available on most linux environments.
Specifically, to install it to your proxVE server,
-- connect as root via SSH
-- issue command in console,
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pvm1:~# apt-get install smartmontools
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Once this is completed, you can issue normal 'smartctl' type command syntax.
for example,
smartctl --device=ata -H /dev/sda
should tell you a brief report on the health of sata drive sda.
Generally, clicking noises on a HDD are very (!) grave signs. If you have not done so already, I would strongly suggest you backup anything of value on this drive, and assume it will fail on you abruptly and without good warning.
--Tim Chipman