Getting Hints Of Problems From The Logs
Most Linux Distributions use systemd now. The journal service of systemd can be very helpful if you want to check your system. I am very interested in error reports, critical system warnings, that sort of problems that require some immediate attention or human intervention.
[donato@archdesktop ~]$ sudo journalctl -f -p 3
[sudo] password for donato:
-- Logs begin at Wed 2017-02-22 07:29:32 +08. --
Mar 06 20:16:44 archdesktop kernel: ata1.00: exception Emask 0x10 SAct 0x0 SErr 0x400100 action 0x6 frozen
Mar 06 20:16:44 archdesktop kernel: ata1.00: irq_stat 0x08000000, interface fatal error
Mar 06 20:16:44 archdesktop kernel: ata1: SError: { UnrecovData Handshk }
Mar 06 20:16:44 archdesktop kernel: ata1.00: cmd a0/00:00:00:08:00/00:00:00:00:00/a0 tag 15 pio 16392 in
opcode=0x4a 4a 01 00 00 10 00 00 00 08 00res 50/00:03:00:08:00/00:00:00:00:00/a0 Emask 0x10 (ATA bus error)
Mar 06 20:16:44 archdesktop kernel: ata1.00: status: { DRDY }
This example is a SATA connection problem. I checked my smartd data with smartctl and nothing insane with them. All disks report healthy. So I am monitoring this if the problem will recur. It could be a bad data / power cable. It could be a bac cable connection. Sometimes merely moving cables around could set this errors on.
You could also set time on the journal output such as:
# journalctl --since "24 hours ago" -p 3 -xb
##the -p flag sets the priority (e.g. 0=system unusable,1=data loss,2=critical,3=errors)
##the -x flag appends some helpful context, messages
##the -b flag limits output to current boot only, since value is empty
