Serviio

I have Synology DS112, Serviio 1.1 , DSM 4.1-2668. No automatic updated library, no online sources, no plugins.
If serviio is stopped, NAS hibernates fine after 10 minutes without wake up.
If serviio is running, NAS hibernates after 10 minutes too, but wakes up periodically each hour (exactly after 60 minutes).


messages
.........
Jan 4 17:03:02 kernel: [453838.610000] ata1: wake up from deepsleep, reset link now
Jan 4 17:03:02 kernel: [453838.690000] ata1: device plugged sstatus 0x123
Jan 4 17:03:02 kernel: [453841.610000] ata1: exception Emask 0x10 SAct 0x0 SErr 0x4010000 action 0xe frozen
Jan 4 17:03:02 kernel: [453841.620000] ata1: edma_err_cause=00000010 pp_flags=00000000, dev connect
Jan 4 17:03:02 kernel: [453841.630000] ata1: SError: { PHYRdyChg DevExch }
Jan 4 17:03:08 kernel: [453847.600000] ata1: link is slow to respond, please be patient (ready=0)
Jan 4 18:03:02 kernel: [457438.640000] ata1: wake up from deepsleep, reset link now
Jan 4 18:03:02 kernel: [457438.720000] ata1: device plugged sstatus 0x123
Jan 4 18:03:02 kernel: [457441.640000] ata1: exception Emask 0x10 SAct 0x0 SErr 0x4010000 action 0xe frozen
Jan 4 18:03:02 kernel: [457441.650000] ata1: edma_err_cause=00000010 pp_flags=00000000, dev connect
Jan 4 18:03:02 kernel: [457441.660000] ata1: SError: { PHYRdyChg DevExch }
Jan 4 18:03:08 kernel: [457447.630000] ata1: link is slow to respond, please be patient (ready=0)
...........

no record in serviio.log (INFO mode, when DEBUG mode is set, NAS never hibernates)

Why is serviio trying to do some action every 60 minutes?