title: mysql - Unable to start mysql
body: <p>I have this error when MySQL wants to start:</p>
  
  <blockquote>
    <p>ERROR! The server quit without updating PID file
    (/usr/local/mysql/var/VM_98_215_centos.pid)</p>
  </blockquote>
  
  <p>And its MySQL error log:</p>
  
  <pre><code>170705 12:50:46 mysqld_safe Starting mysqld daemon with databases from       /usr/local/mysql/var
  170705 12:50:46 [Note] /usr/local/mysql/bin/mysqld (mysqld 5.5.48-log)   starting as process 9091 ...
  170705 12:50:46 [Note] Plugin 'FEDERATED' is disabled.
  170705 12:50:46 InnoDB: The InnoDB memory heap is disabled
  170705 12:50:46 InnoDB: Mutexes and rw_locks use GCC atomic builtins
  170705 12:50:46 InnoDB: Compressed tables use zlib 1.2.7
  170705 12:50:46 InnoDB: Initializing buffer pool, size = 16.0M
  170705 12:50:46 InnoDB: Completed initialization of buffer pool
  170705 12:50:46 InnoDB: highest supported file format is Barracuda.
  InnoDB: The log sequence number in ibdata files does not match
  InnoDB: the log sequence number in the ib_logfiles!
  170705 12:50:46  InnoDB: Database was not shut down normally!
  InnoDB: Starting crash recovery.
  InnoDB: Reading tablespace information from the .ibd files...
  InnoDB: Restoring possible half-written data pages from the doublewrite
  InnoDB: buffer...
  InnoDB: Last MySQL binlog file position 0 2437158, file name ./mysql- bin.000030
  170705 12:50:46  InnoDB: Waiting for the background threads to start
  170705 12:50:47 InnoDB: 5.5.48 started; log sequence number 7592792
  170705 12:50:47 [Note] Recovering after a crash using mysql-bin
  170705 12:50:47 [ERROR] Error in Log_event::read_log_event(): 'read  error', data_len: 75, event_type: 23
  170705 12:50:47 [Note] Starting crash recovery...
  170705 12:50:47 [Note] Crash recovery finished.
  04:50:47 UTC - mysqld got signal 11 ;
  This could be because you hit a bug. It is also possible that this     binary
  or one of the libraries it was linked against is corrupt, improperly   built,
  or misconfigured. This error can also be caused by malfunctioning     hardware.
  We will try our best to scrape up some info that will hopefully help
  diagnose the problem, but since we have already crashed, 
  something is definitely wrong and this may fail.
  
  key_buffer_size=16777216
  read_buffer_size=262144
  max_used_connections=0
  max_threads=500
  thread_count=0
  connection_count=0
  It is possible that mysqld could use up to 
  key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads =     406149 K  bytes of memory
  Hope that's ok; if not, decrease some variables in the equation.
  
  Thread pointer: 0x0
  Attempting backtrace. You can use the following information to find out
  where mysqld died. If you see no messages after this, something went
  terribly wrong...
  stack_bottom = 0 thread_stack 0x40000
  /usr/local/mysql/bin/mysqld(my_print_stacktrace+0x20)[0x75f310]
  /usr/local/mysql/bin/mysqld(handle_fatal_signal+0x359)[0x657d79]
  /usr/lib64/libpthread.so.0(+0xf370)[0x7f32eef57370]
  The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html     contains
  information that should help you find out what is causing the crash.
  170705 12:50:47 mysqld_safe mysqld from pid file     /usr/local/mysql/var/VM_98_215_centos.pid ended
  </code></pre>
  
  <p>Thank you in advance!</p>
  
  <h1>rpm -q centos-release</h1>
  
  <p>centos-release-7-3.1611.el7.centos.x86_64</p>