Hey, my server is rebooting from time to time , i've check the error logs files of apache , system and nothing is showing there . my server RAM is 24GB RAM ( Debian GNU/Linux 8 ), 24 Core processor of Intel(R) Xeon(R) CPU L5639 . the server is for converting video/audio files using ffmpeg . here is the last command output that show the reboots time : root@box1:~# last root pts/0 #.249.227.146 Sun May 31 22:21 still logged in reboot system boot 3.16.0-4-amd64 Sun May 31 12:12 - 22:22 (10:09) reboot system boot 3.16.0-4-amd64 Sun May 31 10:50 - 22:22 (11:32) root pts/0 #.158.134.152 Sun May 31 08:27 - 08:27 (00:00) root pts/0 #.158.134.152 Sun May 31 06:18 - 06:18 (00:00) reboot system boot 3.16.0-4-amd64 Sat May 30 15:28 - 22:22 (1+06:53) reboot system boot 3.16.0-4-amd64 Sat May 30 14:32 - 22:22 (1+07:50) reboot system boot 3.16.0-4-amd64 Sat May 30 14:28 - 22:22 (1+07:53) reboot system boot 3.16.0-4-amd64 Sat May 30 14:22 - 22:22 (1+07:59) reboot system boot 3.16.0-4-amd64 Sat May 30 14:17 - 22:22 (1+08:04) reboot system boot 3.16.0-4-amd64 Sat May 30 14:11 - 22:22 (1+08:10) reboot system boot 3.16.0-4-amd64 Sat May 30 13:06 - 22:22 (1+09:15) root pts/0 #.158.153.239 Thu May 28 01:55 - 02:06 (00:10) reboot system boot 3.16.0-4-amd64 Wed May 27 09:05 - 22:22 (4+13:17) reboot system boot 3.16.0-4-amd64 Wed May 27 08:45 - 22:22 (4+13:37) root pts/0 #.158.158.32 Tue May 26 12:39 - 12:39 (00:00) reboot system boot 3.16.0-4-amd64 Mon May 25 21:52 - 22:22 (6+00:30) reboot system boot 3.16.0-4-amd64 Mon May 25 21:48 - 22:22 (6+00:34) root pts/0 #.249.211.66 Mon May 25 14:26 - 14:27 (00:01) root pts/0 #.249.231.191 Sun May 24 21:08 - 21:08 (00:00) root pts/0 ##-46-90-21 Sat May 23 13:11 - 13:37 (00:26) root pts/0 #.158.155.108 Fri May 22 22:06 - 22:06 (00:00) root pts/0 #.249.216.155 Fri May 22 17:58 - 17:58 (00:00) root pts/0 #.158.155.108 Fri May 22 13:05 - 13:08 (00:02) root pts/0 #.158.155.108 Fri May 22 12:57 - 13:03 (00:05) reboot system boot 3.16.0-4-amd64 Fri May 22 06:09 - 22:22 (9+16:12) reboot system boot 3.16.0-4-amd64 Fri May 22 04:56 - 22:22 (9+17:25) root pts/0 #.249.204.112 Fri May 22 00:47 - 01:58 (01:11) reboot system boot 3.16.0-4-amd64 Thu May 21 23:29 - 22:22 (9+22:52) root pts/0 #.249.204.112 Thu May 21 23:12 - crash (00:17) reboot system boot 3.16.0-4-amd64 Thu May 21 22:53 - 22:22 (9+23:28) reboot system boot 3.16.0-4-amd64 Thu May 21 20:08 - 22:22 (10+02:14) reboot system boot 3.16.0-4-amd64 Thu May 21 19:04 - 22:22 (10+03:18) reboot system boot 3.16.0-4-amd64 Thu May 21 17:32 - 22:22 (10+04:49) root pts/0 #.249.204.112 Thu May 21 16:20 - 16:# (00:21) reboot system boot 3.16.0-4-amd64 Wed May 20 02:16 - 22:22 (11+20:05) reboot system boot 3.16.0-4-amd64 Wed May 20 01:49 - 22:22 (11+20:32) root pts/0 ##-75-88-21 Wed May 20 00:39 - crash (01:09) reboot system boot 3.16.0-4-amd64 Tue May 19 20:20 - 22:22 (12+02:02) reboot system boot 3.16.0-4-amd64 Tue May 19 19:21 - 22:22 (12+03:00) reboot system boot 3.16.0-4-amd64 Tue May 19 04:59 - 22:22 (12+17:22) reboot system boot 3.16.0-4-amd64 Tue May 19 04:33 - 22:22 (12+17:49) reboot system boot 3.16.0-4-amd64 Tue May 19 04:15 - 22:22 (12+18:06) reboot system boot 3.16.0-4-amd64 Tue May 19 04:05 - 22:22 (12+18:16) reboot system boot 3.16.0-4-amd64 Mon May 18 20:13 - 22:22 (13+02:08) reboot system boot 3.16.0-4-amd64 Mon May 18 17:05 - 22:22 (13+05:16) reboot system boot 3.16.0-4-amd64 Mon May 18 16:54 - 22:22 (13+05:27) reboot system boot 3.16.0-4-amd64 Mon May 18 13:56 - 22:22 (13+08:25) reboot system boot 3.16.0-4-amd64 Mon May 18 13:50 - 22:22 (13+08:32) root pts/0 #.155.231.34 Mon May 18 10:55 - crash (02:54) reboot system boot 3.16.0-4-amd64 Mon May 18 03:20 - 22:22 (13+19:01) reboot system boot 3.16.0-4-amd64 Mon May 18 01:54 - 22:22 (13+20:27) root pts/0 #.155.224.194 Sun May 17 11:04 - 11:04 (00:00) root pts/0 #.155.224.194 Sat May 16 23:15 - 01:07 (01:51) root pts/0 #.155.224.194 Sat May 16 22:08 - 22:27 (00:19) root pts/2 #.155.224.194 Sat May 16 18:32 - 18:33 (00:00) root pts/1 #.155.224.194 Sat May 16 18:32 - 18:33 (00:00) root pts/0 #.155.224.194 Sat May 16 17:29 - 18:33 (01:04) root pts/0 #.158.154.127 Fri May 15 11:24 - 11:27 (00:02) root pts/0 #.158.154.127 Thu May 14 23:04 - 23:05 (00:00) reboot system boot 3.16.0-4-amd64 Thu May 14 15:18 - 22:22 (17+07:03) reboot system boot 3.16.0-4-amd64 Thu May 14 09:07 - 22:22 (17+13:14) reboot system boot 3.16.0-4-amd64 Wed May 13 14:33 - 22:22 (18+07:48) reboot system boot 3.16.0-4-amd64 Wed May 13 02:59 - 22:22 (18+19:22) reboot system boot 3.16.0-4-amd64 Wed May 13 01:32 - 22:22 (18+20:49) root pts/0 ##-153-88-2 Tue May 12 11:47 - 12:22 (00:34) root pts/0 #.249.#.32 Tue May 12 01:43 - 02:03 (00:19) root pts/1 #.249.220.82 Mon May 11 03:23 - 03:25 (00:02) root pts/0 #.249.220.82 Mon May 11 03:19 - 03:25 (00:06) root pts/0 #.158.135.186 Sat May 9 23:40 - 23:43 (00:03) root pts/0 #.158.135.186 Sat May 9 20:56 - 20:57 (00:00) root pts/0 #.249.218.173 Sat May 9 06:29 - 06:30 (00:01) root pts/0 #.249.205.# Fri May 8 11:16 - 11:16 (00:00) root pts/0 #.249.205.# Fri May 8 01:54 - 01:55 (00:00) reboot system boot 3.16.0-4-amd64 Thu May 7 16:51 - 22:22 (24+05:31) root pts/1 ##-29-88-21 Thu May 7 15:44 - 16:05 (00:20) root pts/0 ##-29-88-21 Thu May 7 15:39 - 16:04 (00:25) reboot system boot 3.16.0-4-amd64 Thu May 7 15:34 - 22:22 (24+06:47) root pts/2 ##-29-88-21 Thu May 7 15:05 - down (00:27) root pts/2 #.249.#.173 Thu May 7 14:18 - 14:18 (00:00) root pts/1 #.249.#.173 Thu May 7 13:43 - down (01:49) root pts/0 #.249.#.173 Thu May 7 12:# - down (02:52) reboot system boot 3.16.0-4-amd64 Thu May 7 12:37 - 15:33 (02:55) root pts/1 #.249.#.173 Thu May 7 11:51 - 11:53 (00:02) root pts/0 #.249.#.173 Thu May 7 11:45 - down (00:49) root pts/0 #.249.218.16 Wed May 6 12:05 - 12:12 (00:07) root pts/0 #.155.231.102 Tue May 5 15:05 - 15:27 (00:22) root pts/0 #.249.229.95 Mon May 4 11:50 - 11:51 (00:00) root pts/0 #.249.205.151 Sat May 2 23:# - 23:42 (00:00) root pts/0 #.249.205.151 Sat May 2 12:43 - 12:54 (00:11) wtmp begins Sat May 2 12:43:08 2015 Code (markup): Please how i can determine and seek the reason of that issue ? and how i can fix that and avoid this downtime . Thanks in advance