因此，服务器（物理）是 CentOS 6.6，运行 VestaCP（apache+nginx+mysql+php），没有其他任何东西。有时（例如当我睡觉时）服务器会毫无预警地宕机。我检查了 /var/log/messages 和 /var/log/secure - 没有可能导致服务器宕机的消息。
有人能至少帮忙找出问题所在吗？
消息日志
Dec 7 02:25:29 24ad named[1402]: client 91.212.124.40#7678: query (cache) 'sukapadla.com.ru/ANY/IN' denied
Dec 7 02:26:40 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 02:36:40 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 02:46:40 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 02:56:40 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 03:06:41 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 03:16:41 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 03:26:41 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 03:36:41 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 03:46:41 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 03:56:41 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 04:06:41 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 04:16:41 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 04:26:41 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 04:36:41 24ad clamd[1500]: SelfCheck: Database status OK.
Dec 7 09:47:18 24ad kernel: imklog 5.8.10, log source = /proc/kmsg started.
Dec 7 09:47:18 24ad rsyslogd: [origin software="rsyslogd" swVersion="5.8.10" x-pid="1385" x-info="http://www.rsyslog.com"] start
Dec 7 09:47:18 24ad kernel: Initializing cgroup subsys cpuset
Dec 7 09:47:18 24ad kernel: Initializing cgroup subsys cpu
Dec 7 09:47:18 24ad kernel: Linux version 2.6.32-504.1.3.el6.x86_64 ([email protected]) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-11) (GCC) ) #1 SMP Tue Nov 11 17:57:25 UTC 2014
..
安全日志
Dec 7 03:33:33 24ad sshd[12327]: pam_unix(sshd:session): session closed for user root
Dec 7 03:54:44 24ad sshd[14658]: Connection closed by 213.239.213.102
Dec 7 03:54:44 24ad sshd[14660]: Connection closed by 208.76.245.135
Dec 7 04:24:44 24ad sshd[16429]: Connection closed by 213.239.213.102
Dec 7 04:24:44 24ad sshd[16431]: Connection closed by 208.76.245.135
Dec 7 09:47:20 24ad sshd[1494]: Server listening on 0.0.0.0 port 1986.
Dec 7 09:47:20 24ad sshd[1494]: Server listening on :: port 1986.
Dec 7 09:49:00 24ad sshd[2281]: Address 178.217.104.88 maps to 178-217-104-88.u-lan.ru, but this does not map back to the address - POSSIBLE BREAK-IN ATTEMPT!
Dec 7 09:49:13 24ad sshd[2281]: Accepted password for root from 178.217.104.88 port 50415 ssh2
Dec 7 09:49:13 24ad sshd[2281]: pam_unix(sshd:session): session opened for user root by (uid=0)
Dec 7 09:49:26 24ad sshd[2298]: Address 178.217.104.88 maps to 178-217-104-88.u-lan.ru, but this does not map back to the address - POSSIBLE BREAK-IN ATTEMPT!
Dec 7 09:49:26 24ad sshd[2298]: Accepted password for root from 178.217.104.88 port 50417 ssh2
Dec 7 09:49:26 24ad sshd[2298]: pam_unix(sshd:session): session opened for user root by (uid=0)
Dec 7 09:49:27 24ad sshd[2298]: subsystem request for sftp
cron日志
Dec 7 04:40:01 24ad CROND[17414]: (root) CMD (/usr/lib64/sa/sa1 1 1)
Dec 7 04:40:01 24ad CROND[17415]: (vnstat) CMD (/usr/sbin/vnstat.cron)
Dec 7 04:40:01 24ad CROND[17416]: (admin) CMD (sudo /usr/local/vesta/bin/v-update-sys-rrd)
Dec 7 04:40:01 24ad CROND[17417]: (admin) CMD (sudo /usr/local/vesta/bin/v-update-sys-queue backup)
Dec 7 04:45:01 24ad CROND[17769]: (admin) CMD (sudo /usr/local/vesta/bin/v-update-sys-rrd)
Dec 7 04:45:01 24ad CROND[17770]: (admin) CMD (sudo /usr/local/vesta/bin/v-update-sys-queue backup)
Dec 7 04:45:01 24ad CROND[17771]: (vnstat) CMD (/usr/sbin/vnstat.cron)
Dec 7 09:47:32 24ad crond[2106]: (CRON) STARTUP (1.4.4)
Dec 7 09:47:32 24ad crond[2106]: (CRON) INFO (RANDOM_DELAY will be scaled with factor 43% if used.)
Dec 7 09:47:32 24ad crond[2106]: (CRON) INFO (running with inotify support)
Dec 7 09:50:01 24ad CROND[2309]: (vnstat) CMD (/usr/sbin/vnstat.cron)
Dec 7 09:50:01 24ad CROND[2311]: (admin) CMD (sudo /usr/local/vesta/bin/v-update-sys-rrd)
Dec 7 09:50:01 24ad CROND[2312]: (root) CMD (/usr/lib64/sa/sa1 1 1)
Dec 7 09:50:01 24ad CROND[2310]: (admin) CMD (sudo /usr/local/vesta/bin/v-update-sys-queue backup)
Dec 7 09:55:01 24ad CROND[2664]: (admin) CMD (sudo /usr/local/vesta/bin/v-update-sys-rrd)
Dec 7 09:55:01 24ad CROND[2665]: (admin) CMD (sudo /usr/local/vesta/bin/v-update-sys-queue backup)
Dec 7 09:55:01 24ad CROND[2666]: (vnstat) CMD (/usr/sbin/vnstat.cron)