I am using a rpi3 with an external usb disk and a 3A power source, but the system seems to turn off after 1-2 days of normal use.
I know that because I cannot access it (ssh or vnc), but there is a red light there.
Then, taking a look at /var/log/messages I think to see when it died, since it stops logging messages 30h ago. Nothing seems out of normal, except for the repetitive (which is also doing it now, just restarted)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.123127] cfg80211: World regulatory domain updated:
Aug 19 05:49:03 raspberrypi kernel: [ 1967.123134] cfg80211: DFS Master region: unset
Aug 19 05:49:03 raspberrypi kernel: [ 1967.123140] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.123150] cfg80211: (2402000 KHz - 2472000 KHz @ 40000 KHz), (N/A, 2000 mBm), (N/A)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.123158] cfg80211: (2457000 KHz - 2482000 KHz @ 40000 KHz), (N/A, 2000 mBm), (N/A)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.123166] cfg80211: (2474000 KHz - 2494000 KHz @ 20000 KHz), (N/A, 2000 mBm), (N/A)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.123175] cfg80211: (5170000 KHz - 5250000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2000 mBm), (N/A)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.123185] cfg80211: (5250000 KHz - 5330000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2000 mBm), (0 s)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.123193] cfg80211: (5490000 KHz - 5730000 KHz @ 160000 KHz), (N/A, 2000 mBm), (0 s)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.123201] cfg80211: (5735000 KHz - 5835000 KHz @ 80000 KHz), (N/A, 2000 mBm), (N/A)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.123209] cfg80211: (57240000 KHz - 63720000 KHz @ 2160000 KHz), (N/A, 0 mBm), (N/A)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.151591] cfg80211: Regulatory domain changed to country: ES
Aug 19 05:49:03 raspberrypi kernel: [ 1967.151609] cfg80211: DFS Master region: ETSI
Aug 19 05:49:03 raspberrypi kernel: [ 1967.151620] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.151630] cfg80211: (2400000 KHz - 2483500 KHz @ 40000 KHz), (N/A, 2000 mBm), (N/A)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.151640] cfg80211: (5150000 KHz - 5250000 KHz @ 80000 KHz, 200000 KHz AUTO), (N/A, 2301 mBm), (N/A)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.151649] cfg80211: (5250000 KHz - 5350000 KHz @ 80000 KHz, 200000 KHz AUTO), (N/A, 2000 mBm), (0 s)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.151658] cfg80211: (5470000 KHz - 5725000 KHz @ 160000 KHz), (N/A, 2698 mBm), (0 s)
Aug 19 05:49:03 raspberrypi kernel: [ 1967.151665] cfg80211: (57000000 KHz - 66000000 KHz @ 2160000 KHz), (N/A, 4000 mBm), (N/A)
Maybe this is completely unrelated. In any case, what can I do to see what's causing this instability of the system? Is it likely to a not good enough power supply?