all domains cannot connect the database

when i tried to launch console via linode control panel, there comes messages:
"li1731-15 login: [ 31.140071] audit: type=1305 audit(1535939096.980:10744): a1
[ 31.145615] audit: type=1305 audit(1535939096.980:10745): audit_enabled=0 ol1
[259852.840218] php-fpm[1079]: segfault at 7ffd0402cf90 ip 0000000000472cee sp ]
[10008614.502130] hrtimer: interrupt took 10396313 ns
[14077402.327408] TCP: request_sock_TCP: Possible SYN flooding on port 21. Send.
[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[A[B"

what that mean?

It looks like your Linode's database has run into a problem. If you're using MySQL you can use the following command to check it's status:

service mysql status

I'd also recommend checking out the logs in /var/log for more info. If you're not able to find the problem, try rebooting your Linode and it may start back up normally.

hi, i found the problem when I used "service mysql status"

it comes
“mysql is running but pid file could not be found”

can you help how to fix it?

i thought it may be too many rabbish files, so I removed these large bin file: mysql-bin.00001 - 00038, it released more than 20g space

but it comes to another problem when restart mysql
"ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/my)"

can anyone help to me fix via console?

i thought it may be too many rabbish files, so I removed these large bin file: mysql-bin.00001 - 00038, it released more than 20g space

These are binary logs and some may still have been necessary.

Your best bet is to check MySql logs in /var/log/mysql.

It may also be necessary to recover the database (now that the binary log files are all gone).

For the future, you do not want to enable binary logs unless you have specific reasons to use them (e.g. replication).

Edit: you may find this useful

https://dba.stackexchange.com/questions/41050

thanks, i fixed it, by removing "log-bin=mysql-bin" in my.cnf