So plenty of reasons, why your NAS HDD are waked up, citing from your post:
StarMox wrote:...download station, that is it.
No, there is more...
StarMox wrote:(would like to start a web server though ...)
...with the NAS configured for a defined list of hostss or subnets? This is why you see the Access Violations below..
StarMox wrote:syslog server is a great idea. my system event log ...
...which is not the syslog server
StarMox wrote:... shows a recording every 10 seconds or so:
2011-09-16 06:06:23 System 127.0.0.1 localhost [Security] Access Violation from 93.103.144.117 with TCP (port=51413)
2011-09-16 06:04:45 System 127.0.0.1 localhost [Security] Access Violation from 86.61.20.38 with TCP (port=51413)
Again, when limiting the access to the NAS to a certain subnetwork, TCP/IP range, or TCP/IP addresses, all other attempts are logged...
StarMox wrote:Interesting, under firmware 3.3.9 qnap showed around 2% CPU usage when idling. Under 3.5.0 it is around 7-10%.
Well, anything you show above is not really idling...a really idling NAS is <0.1% CPU
StarMox wrote: 3396 admin S 5360 1 2.8 2.0 btd
4578 admin S 11M 1 0.9 4.4 transmission-da
So beyond the Download Station, also Transmission is active...paired with a useless "high" security setting when running download services, limiting access to a defined addresses and networks, this is triggering the access violations above.
StarMox wrote:manarequest, sysrequest? 7.5 % ?
Most likely triggered by Web UI activities, still ongoing ACL changes after access right modifications, security logging, ...