MySQL 8.0 FAQ: MySQL Chinese, Japanese, and Korean Character Sets MySQL NDB Cluster does not provide any sort of automatic failover between SQL nodes. Your application must be prepared to handle the loss of SQL nodes and to fail over between them. You can use the NDB Cluster native backup and restore functionality in the NDB management client and the  ndb_restore  program. See Section 23.5.8, “Online Backup of NDB Cluster” , and Section 23.4.23, “ndb_restore — Restore an NDB Cluster Backup” . You can also use the traditional functionality provided for this purpose in  mysqldump  and the MySQL server. See Section 4.5.4, “mysqldump — A Database Backup Program” , for more information. This process monitors and, if necessary, attempts to restart the data node process. If you check the list of active processes on your system after starting  ndbd , you can see that there are actually 2 processes running by that name, as shown here (we omit the output from  ndb_mgmd  and  ndbd  for brevity): The  ndbd  process showing  0.0  for both memory and CPU usage is the angel process (although it actually does use a very small amount of each). This process merely checks to see if the main  ndbd or  ndbmtd  process (the primary data node process which actually handles the data) is running. If permitted to do so (for example, if the  StopOnError  configuration parameter is set to  false ), the angel process tries to restart the primary data node process. This set of Frequently Asked Questions derives from the experience of MySQL’s Support and Development groups in handling many inquiries about CJK (Chinese-Japanese-Korean) issues. shell>  ./ndb_mgmd shell>  ps aux | grep ndb me 23002 0.0 0.0 122948 3104 ? Ssl 14:14 0:00 ./ndb_mgmd me 23025 0.0 0.0 5284 820 pts/2 S+ 14:14 0:00 grep ndb shell>  ./ndbd -c 127.0.0.1 --initial shell>  ps aux | grep ndb me 23002 0.0 0.0 123080 3356 ? Ssl 14:14 0:00 ./ndb_mgmd me 23096 0.0 0.0 35876 2036 ? Ss 14:14 0:00 ./ndbmtd -c 127.0.0.1 --initial me 23097 1.0 2.4 524116 91096 ? Sl 14:14 0:00 ./ndbmtd -c 127.0.0.1 --initial me 23168 0.0 0.0 5284 812 pts/2 R+ 14:15 0:00 grep ndb A.11 MySQL 8.0 FAQ: MySQL Chinese, Japanese, and Korean Character Sets 5257 A.10.39. How do I continue to send queries in the event that one of the SQL nodes fails? A.10.41. What is an “angel process” ? A.10.40. How do I back up and restore an NDB Cluster? A.11.1 What CJK character sets are available in MySQL? .............................................................. 5258 A.11.2 I have inserted CJK characters into my table. Why does  SELECT  display them as “?” characters? ......................................................................................................................... 5259 A.11.3 What problems should I be aware of when working with the Big5 Chinese character set? ....... 5261 A.11.4 Why do Japanese character set conversions fail? ............................................................... 5261 A.11.5 What should I do if I want to convert SJIS  81CA  to  cp932 ? ................................................. 5262 A.11.6 How does MySQL represent the Yen ( ¥ ) sign? ................................................................... 5262 A.11.7 Of what issues should I be aware when working with Korean character sets in MySQL? ......... 5263 A.11.8 Why do I get  Incorrect string value  error messages? .............................................. 5263