Question
centos 8 mysql keeps stoped status
mysql craahed tarting today, and it keeps down. what I get if I want to restar mysql service
systemctl restart mysqld
Job for mysqld.service failed because the control process exited with error code.
See "systemctl status mysqld.service" and "journalctl -xe" for details.
my error log
2020-10-19T09:10:14.068125Z 0 [System] [MY-010116] [Server] /usr/libexec/mysqld (mysqld 8.0.21) starting as process 320061
2020-10-19T09:10:14.088157Z 1 [System] [MY-013576] [InnoDB] InnoDB initialization has started.
2020-10-19T09:10:14.145172Z 0 [ERROR] [MY-012681] [InnoDB] mmap(137363456 bytes) failed; errno 12
2020-10-19T09:10:14.145376Z 1 [ERROR] [MY-012956] [InnoDB] Cannot allocate memory for the buffer pool
2020-10-19T09:10:14.145460Z 1 [ERROR] [MY-012930] [InnoDB] Plugin initialization aborted with error Generic error.
2020-10-19T09:10:14.145573Z 1 [ERROR] [MY-010334] [Server] Failed to initialize DD Storage Engine
2020-10-19T09:10:14.145831Z 0 [ERROR] [MY-010020] [Server] Data Dictionary initialization failed.
2020-10-19T09:10:14.145973Z 0 [ERROR] [MY-010119] [Server] Aborting
2020-10-19T09:10:14.146611Z 0 [System] [MY-010910] [Server] /usr/libexec/mysqld: Shutdown complete (mysqld 8.0.21) Source distribution.
journalctl -xe
Oct 19 09:11:03 centos-s-1vcpu-1gb-sgp1-01 sshd[320118]: Invalid user 111111 from 185.153.196.230 port 32742
Oct 19 09:11:03 centos-s-1vcpu-1gb-sgp1-01 sshd[320118]: pam_unix(sshd:auth): check pass; user unknown
Oct 19 09:11:03 centos-s-1vcpu-1gb-sgp1-01 sshd[320118]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=185.153.196.230
Oct 19 09:11:05 centos-s-1vcpu-1gb-sgp1-01 sshd[320118]: Failed password for invalid user 111111 from 185.153.196.230 port 32742 ssh2
Oct 19 09:11:06 centos-s-1vcpu-1gb-sgp1-01 sshd[320118]: pam_unix(sshd:auth): check pass; user unknown
Oct 19 09:11:08 centos-s-1vcpu-1gb-sgp1-01 sshd[320118]: Failed password for invalid user 111111 from 185.153.196.230 port 32742 ssh2
Oct 19 09:11:09 centos-s-1vcpu-1gb-sgp1-01 sshd[320118]: Disconnecting invalid user 111111 185.153.196.230 port 32742: Change of username or service not allowed: (111111,ssh-connection) -> (admin,ssh-connectio>
Oct 19 09:11:09 centos-s-1vcpu-1gb-sgp1-01 sshd[320118]: PAM 1 more authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=185.153.196.230
from the error log looks like a memory issue so i run free -mh command
free -mh
total used free shared buff/cache available
Mem: 818Mi 296Mi 291Mi 101Mi 230Mi 297Mi
Swap: 0B 0B 0B
I used of 296m but i cache 230m i should supposed to have decent amount of memory I can used am I right ? https://www.digitalocean.com/community/questions/out-of-memory-is-it-possible
from the answer of this post , this is the what he said
To expand on the “used” RAM above, simply because I’ve “used” 1.9GB out of the 2GB I’ve been allocated does not mean that I’ve used that much. The 1.6GB’s from the cache column is included in that 1.9GB’s, so my actual usage is only ~300MB. The other 1.3GB is cached and used by current processes until they are either stopped, killed or restarted
but once i take a close look at journalctl -xe log , there is a user 111111 trying to login with wrong password ??
Failed password for invalid user 111111 from 185.153.196.230 port 32742 ssh2
I dont know if this is actually a memory problem or another issues ?? hopefully someone have infra knowledge can advise me on this .thanks now all of my site is down , I am using the cheapest droplet instance. which have 1G memory. btw , I am using centos8 nginx, php , mysql stack.thanks again.
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Hello there,
In addition to what has already been mentioned, I wanted to point out that CentOS Linux 8 has reached End Of Life (EOL) on December 31st, 2021.
I would strongly recommend planning either migration to another OS like Debian or Ubuntu, or upgrading to CentOS Stream.
I personally believe that the safest way to do this is to follow these steps here:
rsyncfor example copy over your files and migrate your databasesRegards, Alex
Hello,
The key error here is:
InnoDB: Fatal error: cannot allocate memory for the buffer poolThis crash is due to your system running out of memory. I’d suggest that you add a swap file to give yourself a bit more of a buffer. Check out this tutorial:
https://www.digitalocean.com/community/tutorials/how-to-add-swap-space-on-ubuntu-20-04
What you can also do is to use the MySQLTuner script.
The MySQLTuner is a script written in Perl and allows you to quickly test your MySQL configuration and it gives you suggestions for adjustments to increase performance and stability.
According to the official GitHub page, it supports 300 indicators for MySQL/MariaDB/Percona Server in this last version.
To run the script you could do the following:
The script would run multiple checks against your MySQL instance, all checks done by MySQLTuner are documented here.
Also as stated in the official documentation, it is still extremely important for you to fully understand each change you make to a MySQL database server. If you don’t understand portions of the script’s output, or if you don’t understand the recommendations, you should consult a knowledgeable DBA or system administrator that you trust.
As a good practice make sure to always test your changes on staging environments before implementing them on your production database.
On the same note, if you want to have a worry-free MySQL hosting and focus on your application, I would recommend trying out the DigitalOcean Managed Databases:
https://www.digitalocean.com/products/managed-databases-mysql/
This was mini tutorial was posted from bobbyiliev in this question in our community: https://www.digitalocean.com/community/questions/how-to-tweak-mysql-mariadb-configuration-for-increased-performance-and-stability
You can also create a simple bash script to check if MySQL is running and if not to restart it.
Run this script every 5 minutes using a cron job like this one:
Hope that this helps! Regards, Alex
The answer depends on the question System OS (CentOS) and MySQL Mariadb service
Solution: Just add some seconds before make service start - in my case I’ve added 45 seconds
Add the following lines under [service] section in {/etc/systemd/system/multi-user.target.wants/mariadb.service} - Of course the path depends on your system OS and MySQL service name (not all have mariadb.service)
Restart=always RestartSec=45s Do NOT forget to run the following commands
sudo systemctl daemon-reload
sudo systemctl restart mariadb.service