11 votes

Server crash with ascii NUL characters in syslog ( ^@^@^@... )

I'll share more widely the great answer given by @n-st: NUL bytes in the syslog are a common effect of a crash that prevented the system from cleanly syncing and unmounting the filesystem. They don'...
anarcat's user avatar
  • 794
10 votes

How to determine cause of system crash?

If you have crashkernel/kdump installed and enabled, you should be able to examine the crashed kernel with relative ease using the crash utility. For example, presuming that your crashed kernel dumps ...
shodanshok's user avatar
  • 50.3k
8 votes

How can you distinguish between a crash and a reboot on RHEL7?

Funny, I just happened to reboot a CentOS 7 system last night, and so I have a nice log of just this to look at. In the case of a crash, obviously nothing is logged between the time of the crash and ...
Michael Hampton's user avatar
7 votes
Accepted

Apache2 Fails to start after recent update to 2.4.34, no clue why

You're missing some of the error. The full error is: apache2: Syntax error on line 146 of /etc/apache2/apache2.conf: Syntax error on line 2 of /etc/apache2/mods-enabled/lbmethod_byrequests.load: ...
Jeff Snider's user avatar
  • 3,282
6 votes

How to determine cause of system crash?

You could check the dmesg file at /var/log/dmesg, which is logging the kernel messages. The messages log is just logging service and application messages and if you have a kernel error, the services ...
TooCloudy's user avatar
6 votes

Why does my debian server freeze?

I had this exact scenario going on. Created a Debian 9 VM under ESXi 6.5 and it would freeze when running a few commands. Also, when I closed an SSH session, it would completely freeze and my only ...
LulzCodr's user avatar
6 votes
Accepted

How can you distinguish between a crash and a reboot on RHEL7?

There's more than one way to do this, but I'll cover the 4 best ones I can think of. (EDIT: I published a cleaned-up version of this as a public article on redhat.com. See: How to distinguish between ...
rsaw's user avatar
  • 253
5 votes

How can you distinguish between a crash and a reboot on RHEL7?

I don't particularly like the answer, but it's an answer we got from RH. I'm posting it here in case it helps someone else. One possible way is to grep for rsyslogd in /var/log/messages. A graceful ...
kwb's user avatar
  • 173
5 votes

KVM based VPS crashes every 3-7 days. Is it an issue on VPS side or node's?

It's probably a backup process or something storage-impacting happening at the host level. This is outside of your control and you should push the VPS provider for a solution. If they can't resolve, ...
ewwhite's user avatar
  • 198k
5 votes
Accepted

Private information in BSOD *.dmp files

A core dump file contains a recording of the memory state of your application/OS/kernel at the time it crashed. The blue screen of death creates a kernel memory dump that can and will contain data ...
HBruijn's user avatar
  • 80k
3 votes

Mysql server crashes without leaving any log behind

It is possible that from time to time MySQL server fall prey of Linux Out-of-Memory (OOM) killer process. You may find traces of such activity in /var/log/syslog or in an output of the dmesg command. ...
RLazar's user avatar
  • 101
3 votes

How to determine cause of system crash?

bios memory test bios hard drive test Check smart drive log smartctl /dev/sda -a Smart drive tests leave dmesg -wH running in a window
Jim U's user avatar
  • 283
3 votes

HP ProLiant ML350p Gen8 server keeps crashing (full speed fans)

There are a couple of reasons this could be happening. Firmware. Updates. possibly hardware. Please see: http://meta.serverfault.com/q/6195/13325 If you're running Windows virtual machines ...
ewwhite's user avatar
  • 198k
3 votes

How unlikely it is that 2 SSD disks in a RAID 1 crash and how to recover from it?

It's quite unlikely but at the same time, not impossible. As always, a RAID is no substitute for a backup. If you don't have a backup, something like this is guaranteed to happen! Recovery: It's ...
Sven's user avatar
  • 99.3k
3 votes

At my wits end. What could cause my server to randomly hard reset? (Seems to be related to ZFS)

Since I've been at my wits end in a similar situation I thought I'd post what ultimately helped me. It might not be exactly related to your situation, but maybe some other poor soul can stumble upon ...
href_'s user avatar
  • 171
2 votes

How to know if the reboot cause is a linux kernel crash?

Type last reboot to see recent reboot reasons and times between reboots. If the system crashed, you may see "crash" in one of the time fields. (root) kppro[1]:~# last reboot reboot system boot 2....
ewwhite's user avatar
  • 198k
2 votes

System crashed - After reboot logs contain "^@"

The caret '^' denotes a control character, '^@' is just the caret notation of the NULL byte.
Sascha K's user avatar
2 votes

Why does my debian server freeze?

If it is a VM, and you can change some parameters, try to set up another type of network adapter, as that looks network related. Also, check also the dmesg output from time to time, even if it is ...
dmoreno's user avatar
  • 166
2 votes

diagnose purple screen of death ESX 6.0

I suggest troubleshooting or following the guidance of the error message. Things you can do: You're running ESXi build #3620759 from March 2016. UPDATE YOUR ESXi INSTALLATION!! HP servers have ...
ewwhite's user avatar
  • 198k
2 votes

Server freezes without kernel panic

This might be a CPU bug. Intel published an errata about this problem and they also provide a microcode update for the E5 v3/v4 CPUs (datecode 20170707). CentOS 7.4 already has a newer microcode ...
Bernhard's user avatar
2 votes

ESXi 6.5 Pink Screen of Death

of course you should use supported hardware if possible. There are also driver-sets for different vendors like HPE or Dell. So it simply could be a driver problem. Another thing that i don't ...
frupfrup's user avatar
  • 853
2 votes

Interpreting SMART Logs of Newly Installed NVMe RAID0 Crashing Everyday

My quick guess would be that the case of the computer has too little ventilation and the environment exceeds new drives' operational temperature range. This triggers device's thermal protection, which ...
Tero Kilkanen's user avatar
2 votes
Accepted

Server crashing every 14 days, no bugcheck

Turns out it was a PSU issue. The weird part is the PSUs never indicated any faults apart from the last crash when their indicator LEDs switched from their usual green to amber. Upon swapping the PSUs ...
gsck's user avatar
  • 31
2 votes

How can I stop my MySQL server from going down?

If you running out of disk space or a similar unexpected event, some of the database tables may have become corrupt. To solve this you need to run this from MYSQL. REPAIR TABLE db_name.table_name;
user1024991's user avatar
2 votes
Accepted

Windows Server 2022 Standard is giving me crashes in the HTTP module that reboot my server. I need help tracking down the exact issue. How?

This is almost certainly related to an update, you are by far not the only one having it https://learn.microsoft.com/en-us/answers/questions/1185893/windows-server-2022-standard-(21h2-20348-1547)-cra ...
GeneMoody-Action1's user avatar
1 vote

PHP script causes server shutdown

Your log shows that some process sent a signal to systemd causing it to shut down, and that the name of the process was kill. Dec 28 04:40:04 www systemd[24724]: Received SIGRTMIN+24 from PID 11820 (...
Michael Hampton's user avatar
1 vote

How to decrese MySQL Innodb crash recovery time (force MySQL to do it faster)

** Also answered on DBA stack exchange, would have commented but not enough points! ** First of all there is a documented bug that has seen the recovery performance of 5.7 degrade, this is discussed ...
greenweeds's user avatar
1 vote

Opening a linux-crashdump dump with crash?

So I figured it out; it seems that the actual meat of the crash dump isn't in the .crash file at all, but instead is inside a folder. The relevant contents of my /var/crash folder therefore looks ...
Haravikk's user avatar
  • 267
1 vote

How to find out why my Ubuntu server is crashing each day

You might want to inspect the syslog if the logging suddenly stopped at some point then resumed showing signs of booting up. This might indicate a server crash due to hardware. RAM issue is possible....
Carlo Miguel Cruz's user avatar
1 vote

Crash utility exit with error in Rhel6.6

I had the same problem on 7.1.5-2.el7: crash: page excluded: kernel virtual address: ffffffff818129b0 type: >"cpu_possible_mask" and upgrading crash version to crash 7.2.3-8.el7 helped.
Jacek Tomaka's user avatar

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