Deploying MySQL Cluster over multiple hosts

This post builds upon the earlier article (Creating a simple Cluster on a single LINUX host) which explained how to install and run a Cluster where all of the nodes run on the same physical host.

The single host solution is not great for a real deployment – MySQL Cluster is designed to provide a High Availability (HA) solution by synchronously replicating data between data nodes – if all of the data nodes run on a single host that that machine is a single point of failure.

MySQL Cluster running accross 2 hosts

MySQL Cluster running accross 2 hosts

This article demonstrates how to split the nodes between hosts; the configuration will still be fairly simple, using just 2 machines but it should be obvious how to extend it to more.

This new Cluster will be split across 2 machines, with all functions duplicated on each machine as shown in the diagram.

Downloading and installing

In the following example, host “ws1″ has the IP Address 192.168.0.3 and “ws2″ has 192.168.0.4.

Browse to the MySQL Cluster LINUX download page at mysql.com and download the correct version (32 or 64 bit) and store it in the desired directory (in my case, /home/billy/mysql) on both hosts and then extract and rename the new folder to something easier to work with…

[billy@ws1 mysql]$ tar xvf mysql-cluster-gpl-7.0.6-linux-x86_64-glibc23.tar.gz
[billy@ws1 mysql]$ mv mysql-cluster-gpl-7.0.6-linux-x86_64-glibc23 7_0_6

[billy@ws2 mysql]$ tar xvf mysql-cluster-gpl-7.0.6-linux-x86_64-glibc23.tar.gz
[billy@ws2 mysql]$ mv mysql-cluster-gpl-7.0.6-linux-x86_64-glibc23 7_0_6

Setup the files that will be needed for the MySQL Server processes (mysqld) to run correctly on each host

[billy@ws1 mysql]$ cd 7_0_6
[billy@ws1 7_0_6]$ scripts/mysql_install_db --basedir=/home/billy/mysql/7_0_6 --datadir=/home/billy/mysql/7_0_6/data

[billy@ws2 mysql]$ cd 7_0_6
[billy@ws2 7_0_6]$ scripts/mysql_install_db --basedir=/home/billy/mysql/7_0_6 --datadir=/home/billy/mysql/7_0_6/data

Configure and run the Cluster

Create a sub-directory called “conf” on each host and create the following 3 files:

config.ini – note that this file is used by the management nodes and as we’re going to run an ndb_mgmd process on each host, this is created on both ws1 and ws2

[ndbd default]
noofreplicas=2

[ndbd]
hostname=192.168.0.3
id=1

[ndbd]
hostname=192.168.0.4
id=2

[ndb_mgmd]
id = 101
hostname=192.168.0.3

[ndb_mgmd]
id = 102
hostname=192.168.0.4

[mysqld]
id=51
hostname=192.168.0.3

[mysqld]
id=52
hostname=192.168.0.4

my.1.confto be used by the MySQL Server on ws1 and so store on ws1

[mysqld]
ndb-nodeid=51
ndbcluster
datadir=/home/billy/mysql/7_0_6/data
basedir=/home/billy/mysql/7_0_6
port=3306
server-id=51
log-bin

my.2.conf - to be used by the MySQL Server on ws2 and so store on ws2

[mysqld]
ndb-nodeid=52
ndbcluster
datadir=/home/billy/mysql/7_0_6/data
basedir=/home/billy/mysql/7_0_6
port=3306
server-id=52
log-bin

Those files configure the nodes that make up the Cluster. From a command prompt window, launch the management nodes:

[billy@ws1 7_0_6]$ bin/ndb_mgmd --initial -f conf/config.ini --configdir=/home/billy/mysql/7_0_6/conf

[billy@ws2 7_0_6]$ bin/ndb_mgmd --initial -f conf/config.ini --configdir=/home/billy/mysql/7_0_6/conf

Check that the management nodes are up and running:

[billy@ws1 7_0_6]$ bin/ndb_mgm
ndb_mgm> show
Connected to Management Server at: localhost:1186
Cluster Configuration
---------------------
[ndbd(NDB)]	2 node(s)
id=1 (not connected, accepting connect from 192.168.0.3)
id=2 (not connected, accepting connect from 192.168.0.4)

[ndb_mgmd(MGM)]	2 node(s)
id=101	@192.168.0.3  (mysql-5.1.34 ndb-7.0.6)
id=102 (not connected, accepting connect from 192.168.0.4)

[mysqld(API)]	2 node(s)
id=51 (not connected, accepting connect from 192.168.0.3)
id=52 (not connected, accepting connect from 192.168.0.4)

ndb_mgm> quit

[billy@ws1 7_0_6]$ bin/ndb_mgm -c 192.168.0.4:1186
ndb_mgm> show
Connected to Management Server at: 192.168.0.4:1186
Cluster Configuration
---------------------
[ndbd(NDB)]	2 node(s)
id=1 (not connected, accepting connect from 192.168.0.3)
id=2 (not connected, accepting connect from 192.168.0.4)

[ndb_mgmd(MGM)]	2 node(s)
id=101 (not connected, accepting connect from 192.168.0.3)
id=102	@192.168.0.4  (mysql-5.1.34 ndb-7.0.6)

[mysqld(API)]	2 node(s)
id=51 (not connected, accepting connect from 192.168.0.3)
id=52 (not connected, accepting connect from 192.168.0.4)
ndb_mgm> quit

and then start the 2 data nodes (ndbd) and 2 MySQL API/Server nodes (mysqld) and then check that they’re all up and running:

[billy@ws1 7_0_6]$ bin/ndbd --initial -c localhost:1186
2009-06-17 13:05:47 [ndbd] INFO     -- Configuration fetched from 'localhost:1186', generation: 1

[billy@ws2 7_0_6]$ bin/ndbd --initial -c localhost:1186
2009-06-17 13:05:51 [ndbd] INFO     -- Configuration fetched from 'localhost:1186', generation: 1

[billy@ws1 7_0_6]$ bin/mysqld --defaults-file=conf/my.1.conf&

[billy@ws2 7_0_6]$ bin/mysqld --defaults-file=conf/my.2.conf&

[billy@ws1 7_0_6]$ bin/ndb_mgm
-- NDB Cluster -- Management Client --
ndb_mgm> show
Connected to Management Server at: localhost:1186
Cluster Configuration
---------------------
[ndbd(NDB)]	2 node(s)
id=1	@127.0.0.1  (mysql-5.1.34 ndb-7.0.6, Nodegroup: 0, Master)
id=2	@192.168.0.4  (mysql-5.1.34 ndb-7.0.6, Nodegroup: 0)

[ndb_mgmd(MGM)]	2 node(s)
id=101	@127.0.0.1  (mysql-5.1.34 ndb-7.0.6)
id=102	@127.0.0.1  (mysql-5.1.34 ndb-7.0.6)

[mysqld(API)]	2 node(s)
id=51	@192.168.0.3  (mysql-5.1.34 ndb-7.0.6)
id=52	@192.168.0.4  (mysql-5.1.34 ndb-7.0.6)
ndb_mgm> quit

Using the Cluster

There are now 2 API nodes/MySQL Servers/mysqlds running on the 2 different hosts; both accessing the same data. Each of those nodes can be accessed by the mysql client using the hostname and ports that were configured in the my.X.cnf files. For example, we can access the first of those nodes (node 51) in the following way (each API node is accessed using the host and port number in its associate my.X.cnf file:

[billy@ws1 7_0_6]$ bin/mysql -h localhost -P 3306
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 4
Server version: 5.1.34-ndb-7.0.6-cluster-gpl-log MySQL Cluster Server (GPL)
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
mysql> use test;
Database changed
mysql> create table assets (name varchar(30) not null primary key,
-> value int) engine=ndb;
Query OK, 0 rows affected (0.99 sec)
mysql> insert into assets values ('Car','1900');
Query OK, 1 row affected (0.03 sec)
mysql> select * from assets;
+------+-------+
| name | value |
+------+-------+
| Car  |  1900 |
+------+-------+
1 row in set (0.00 sec)
mysql> quit
Bye

If you see “ERROR 1130 (HY000): Host ‘192.168.0.3’ is not allowed to connect to this MySQL server” then you need to set up the privileges (repeat on each host) – in a real system, you’d likely want tighter security that this:

[billy@ws1 7_0_6]$ bin/mysql -u root
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 3
Server version: 5.1.34-ndb-7.0.6-cluster-gpl-log MySQL Cluster Server (GPL)
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
mysql> GRANT ALL ON *.* TO ''@'localhost';
Query OK, 0 rows affected (0.00 sec)
mysql> GRANT ALL ON *.* TO ''@'192.168.0.4';
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Bye

[billy@ws2 7_0_6]$ bin/mysql -u root
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 8
Server version: 5.1.34-ndb-7.0.6-cluster-gpl-log MySQL Cluster Server (GPL)
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
mysql> GRANT ALL ON *.* TO ''@'localhost';
Query OK, 0 rows affected (0.01 sec)
mysql> GRANT ALL ON *.* TO ''@'192.168.0.3';
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Bye

Note that as this table is using the ndb (MySQL Cluster) storage engine, the data is actually held in the data nodes rather than in the SQL node and so we can access the exact same data from the the other SQL nodes:

[billy@ws1 7_0_6]$ bin/mysql -h 192.168.0.4 -P 3306
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 10
Server version: 5.1.34-ndb-7.0.6-cluster-gpl-log MySQL Cluster Server (GPL)
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select * from assets;
+------+-------+
| name | value |
+------+-------+
| Car  |  1900 |
+------+-------+
1 row in set (0.01 sec)
mysql> quit
Bye

Your next steps

This is still a fairly simple, contrived set up. Hopefully it’s clear how additional data or SQL nodes could be added and in a larger deployment you may well decide to run the management and SQL nodes on different hosts to the data nodes (in fact, when starting up the management nodes there is a warning message suggesting you deploy them elsewhere!).

To move the management node to a 3rd, independent physical host (and a 4th one if you want 2 management nodes for redundancy -a future article will explain when you might want to do that),  just change the IP address in the  [ndb_mgmd] section of config.ini and then run the ndb_mgmd executable on that new host. Note that the management node consumes very few resources and so can share that host with other functions/applications (e.g. SQL Server nodes but not data nodes).

You’d also set several more variables in the configuration files in order to size and tune your Cluster.

In this article, I used 2 LINUX hosts but you could extend the Windows example introduced in My first Cluster running on Windows in exactly the same way.





92 comments

  1. […] physical hosts in the interests of performance and redundancy (take a look at the new article (Deploying MySQL Cluster over multiple host) to see how to do that). You’d also set several more variables in the configuration files in […]

  2. […] will focus on setting up the replication, you can refer to Deploying MySQL Cluster over multiple hosts for the steps to configure and run each MySQL Cluster […]

  3. Umarzuki says:

    What about error:
    Can’t connect to local mysql server through socket ‘/tmp/mysql.sock’ ?

    • admin says:

      That implies that the mysqld is using a non-standard location for its socket. A couple of options:

      connect using the IP Address/port number: mysql -h 192.168.0.4 -P 3306 (where the port number is defined in the defaults file that you specify when starting mysqld)
      When you start the mysqld process, it should tell you the location it’s using for the socket; you can then specify that location using the “mysql -S” option
      Specify where you want the socket in the defaults file you use when starting mysqld by including “socket=/tmp/mysql.sock” which is where the mysql is looking by default (obviously, each mysqld on the same host would need to use a different socket

      Regards, Andrew.

  4. Harikrishna.gangi says:

    Hi,
    This setup works perfectly for with out errors

    Regards,
    Hari

  5. bin3r says:

    Hi
    I want to used 3 hosts in mysql-cluster.
    2 node for ndbd, and 1 node for ndb_mgmnd,
    can you show me the tutorial

    thanks

  6. Jordan says:

    Just a quick note to say “Thank you”. This post was extremely helpful in understanding the basics of how each piece of the MySQL cluster works together. Thank you for taking the time to share this with the community.

  7. Michiel says:

    DO I create the my.1.cnf and my.2.cnf on both servers?
    If so, I get the following error:

    -bash-3.2# bin/ndb_mgmd –initial -f conf/config.ini –configdir=/usr/local/mysql-cluster/conf
    2010-04-21 13:39:16 [MgmtSrvr] INFO — NDB Cluster Management Server. mysql-5.1.41 ndb-7.0.13
    2010-04-21 13:39:16 [MgmtSrvr] INFO — Reading cluster configuration from ‘conf/config.ini’
    2010-04-21 13:39:16 [MgmtSrvr] WARNING — at line 26: Cluster configuration warning:
    arbitrator with id 101 and db node with id 1 on same host 194.145.200.17
    arbitrator with id 102 and db node with id 2 on same host 194.145.200.171
    Running arbitrator on the same host as a database node may
    cause complete cluster shutdown in case of host failure.
    2010-04-21 13:39:17 [MgmtSrvr] INFO — Reading cluster configuration from ‘conf/config.ini’
    2010-04-21 13:39:17 [MgmtSrvr] WARNING — at line 26: Cluster configuration warning:
    arbitrator with id 101 and db node with id 1 on same host 194.145.200.17
    arbitrator with id 102 and db node with id 2 on same host 194.145.200.171
    Running arbitrator on the same host as a database node may
    cause complete cluster shutdown in case of host failure.

    server1=194.145.200.17
    server2=194.145.200.171

    What could be wrong?

    • admin says:

      Hi Michiel,

      there should be just one instance of each my.*.cnf file and each my.*.cnf file should be used with just one mysqld process. It looks like you’re trying to run 2 mysqld processes who have the same id defined in their my.*.cnf file.

      Regards, Andrew.

  8. […] A series of quick-start guides are now available to get you up and running with MySQL Cluster in as little time as possible; they are available for LINUX/Mac OS X, Windows and Solaris. The configuration is intentionally a simple one – 2 data nodes, 1 management node and 1 MySQL Server. Once you have this up and running, your next experiment may be to extend this over multiple hosts. […]

  9. Hi Andrew,

    Will it be necessary for the data nodes(say 2), management nodes(2) and the mysqld(2) nodes to be deployed in different machines (total of 6 machines)? Or just 4(2 data+mysqld nodes + 2 management nodes)?

    Would you think implementing MySQL cluster in a virtualized(Xen) environment good? My current setup would have two physical servers (8GB available each), no SAN, each machine hosting three VMs (VM for manager, VM for data+sqld #1, VM for data+sqld #2). Totaling 6 VMs overall.

  10. […] I prefer installing MySQL Cluster from the tar ball as it gives me more control (for example, openSUSE is using MySQL Cluster 7.0 but I prefer to use […]

  11. Mohsin says:

    Hello

    I did exactly what u said here .

    After creating the config.ini and my.conf file

    when i try to start management node i get the error

    ./ndb_mgmd: unknown option ‘–ndbcluster’

    Can you help me

    Thanks

  12. Mohsin says:

    It worked thanks

  13. Epico says:

    Is it possible to have mysql node on windows and datanodes on linux?

    • admin says:

      Hi Epico,

      Yes – you could have MySQL Servers on Windows with Data Nodes on LINUX. The restriction to watch out for is that the MySQL Servers (and any other NDB API client) needs to be running on an architecture with the same endienness as the data nodes.

      Andrew.

  14. Tamer says:

    I found this very helpfull. I was able to get the cluster setup and working but at 18,080 rows in one of my tables. I get a table full error.

    I am using 3 linux boxes running Ubuntu 9. and each box has 4gb of ram. Any help resolving this is greatly appreciated.

    Thanks

    • admin says:

      Hi Tamer,

      Great to hear that you’re up and running.

      Did you set the DataMemory parameter in your config.ini? If not then the default is 80Mbytes and you may have hit that: http://dev.mysql.com/doc/refman/5.1/en/mysql-cluster-ndbd-definition.html#ndbparam-ndbd-datamemory

      To check, run “ALL REPORT MEMORY” from within the ndb_mgm tool.

      You may need to increase IndexMemory too.

      Once you’ve edited your config.ini file, shut down the ndb_mgmd process and then start it again with the –initial option. Then restart each of your data nodes in turn (wait for the 1st data node to come back up before restarting the next one to avoid an outage) – do *not* use the –initial option when starting the data nodes unless you want to remove all of your data.

      Andrew.

  15. somecallmemike says:

    Great post got it working right away. I was hoping you could explain why the cluster warns that running the management server on the same host as the data node is not advised? I did some googling and couldn’t find a definitive answer.

    Thanks!

  16. Thomas says:

    I’ve set up my MySQL-Cluster as you expected (adding some additional variables), it started fine, but:

    root@zm2:/etc/mysql# ndb_mgm
    — NDB Cluster — Management Client —
    ndb_mgm> show
    Connected to Management Server at: localhost:1186
    Cluster Configuration
    ———————
    [ndbd(NDB)] 2 node(s)
    id=1 @192.168.180.44 (mysql-5.1.39 ndb-7.0.9, Nodegroup: 0, Master)
    id=2 @127.0.0.1 (mysql-5.1.39 ndb-7.0.9, Nodegroup: 0)

    [ndb_mgmd(MGM)] 2 node(s)
    id=101 @127.0.0.1 (mysql-5.1.39 ndb-7.0.9)
    id=102 @127.0.0.1 (mysql-5.1.39 ndb-7.0.9)

    [mysqld(API)] 2 node(s)
    id=51 (not connected, accepting connect from 192.168.180.44)
    id=52 (not connected, accepting connect from 192.168.180.45)

    ndb_mgm>

    mysqld is running. And I have configured:
    [mysqld]
    ndb-nodeid = 51
    server-id = 51
    ndb-cluster
    ndb-connectstring = 192.168.180.44

    [mysql_cluster]
    ndb-connectstring = 192.168.180.44

    Since there is no error message and I couldn’t find anything — why doesn’t connect mysqld to the management daemon?

    A little bit lost …

    • admin says:

      Thomas, the first thing I would do is to replace 127.0.0.1 with the real IP address (192.168.180.??). 127.0.0.1 only makes sense on that machine whereas the configuration data needs to be shared and interpreted on all hosts in the Cluster.

      Please let me know how you get on.

      Regards, Andrew.

  17. aktheus says:

    I’m a newbie, jeje, but i found your post very clear, thanks a lot. I’m going to use it for my very first distributed architecture proyect (I’m a student). Hope everything goes well.

  18. IKetut gunawan says:

    Hi Andrew ,
    I have done to try .
    Fist time clustering runing well , but after restart my window and runing again the second server mgm error “failed to report event to event log, error: 1502

    can you give sugestion .

    Thanks you .
    IKetutG

    • admin says:

      IKetut,

      to get more information, if you were using the start /B approach then try without it (you’ll need more windows to cope with the number of processes). After that check the log files that are created – there should be some clues there.

      Regards, Andrew.

  19. neel says:

    very very good article…each n everything is mentioned in a clear way…helpful for the beginers….

    thanks…
    Neel

  20. Indravardhan says:

    It worked like charm.

    Thanks.

  21. Ruto says:

    I have configure everything as indicated in the post but I keep getting this message.

    MySQL Cluster Management Server mysql-5.1.56 ndb-7.0.30
    2012-03-13 17:50:15 [MgmtSrvr] WARNING — at line 27: Cluster configuration warning:
    arbitrator with id 101 and db node with id 1 on same host 196.168.1.189
    arbitrator with id 102 and db node with id 2 on same host 196.168.1.187
    Running arbitrator on the same host as a database node may
    cause complete cluster shutdown in case of host failure.

    ruto@rutoc:~/mysql/7_0_6$

    My.1.cnf exist in one machine and my.2.cnf exist on another machine while config.ini exist in both.What might be the problem? am using ubuntu 11.10.

  22. Quang Thanh says:

    I have Some error when i run
    bin/mysqld –defaults-file=conf/my.2.conf&

    And see this report.

    [root@localhost cluster]# 120619 1:52:55 [ERROR] Can’t find messagefile ‘/var/tmp/cluser/share/english/errmsg.sys’
    120619 1:52:55 [Warning] Can’t create test file /var/tmp/cluser/data/localhost.lower-test
    120619 1:52:55 [Warning] Can’t create test file /var/tmp/cluser/data/localhost.lower-test
    bin/mysqld: Can’t change dir to ‘/var/tmp/cluser/data/’ (Errcode: 2)

    Plz help me fix it.

    • andrew says:

      Quang,

      Are you sure that you ran mysql-installdb for the datadir’s that you’re using for your mysqlds?

      Andrew.

  23. Balaji says:

    Andrew,

    I installed mysql-5.5.20 ndb-7.2.5 but the data is not replicating from API to nodes or within nodes

    ndb_mgm> show
    Cluster Configuration
    ———————
    [ndbd(NDB)] 2 node(s)
    id=2 @10.100.100.203 (mysql-5.5.20 ndb-7.2.5, Nodegroup: 0, Master)
    id=3 @10.100.100.204 (mysql-5.5.20 ndb-7.2.5, Nodegroup: 0)

    [ndb_mgmd(MGM)] 1 node(s)
    id=1 @10.100.100.206 (mysql-5.5.20 ndb-7.2.5)

    [mysqld(API)] 1 node(s)
    id=4 @10.100.100.205 (mysql-5.5.20 ndb-7.2.5)

    ndb_mgm> 4 status
    Node 4: connected (Version 7.2.5)

    ndb_mgm>

    created a table in API (10.100.100.205)
    mysql> use test;
    mysql> CREATE TABLE `test` ( `id` int(11) DEFAULT NULL ) ENGINE=ndbcluster DEFAULT CHARSET=latin1;
    Query OK, 0 rows affected (0.08 sec)

    but the table is not showing up in any of the nodes.

    • andrew says:

      Balaji,

      what makes you think that the data hasn’t been written to the data nodes? The normal way you’d check that it has would be reading the same data through another MySQL Server (mysqld) that is part of the same cluster. Judging by the output from ndb_mgm, you only have a single mysqld.

      My bet is that the data is in fact being written to both data nodes – I see no reason to suspect otherwise.

      Regards, Andrew.

  24. Balaji says:

    Andrew,

    I was trying to understand where the data is stored in the datanodes, so I did the following

    1. Created a test table in test database
    2. I see this table is stored here in SQL node
    [root@slave05 test]# pwd
    /usr/local/mysql/data/test
    [root@slave05 test]# ls -ltr
    total 12
    -rw-rw—- 1 mysql mysql 0 Jun 25 10:33 test.ndb
    -rw-rw—- 1 mysql mysql 8556 Jun 25 10:33 test.frm

    3. Then I wanted to find out if this table is replicated to data nodes. But it isn’t.
    [root@slave03 test]# pwd
    /usr/local/mysql/data/test
    [root@slave03 test]# ls -ltr
    total 0
    [root@slave03 test]#

    [root@slave04 test]# pwd
    /usr/local/mysql/data/test
    [root@slave03 test]# ls -ltr
    total 0
    [root@slave03 test]#

    slave05 is SQL node
    slave03 and slave04 are data node

    How/where to check if the data is written on data node?.

    • andrew says:

      What you’re seeing on the MySQL servers is the data dictionary rather than the data itself. On the data nodes, there isn’t a different file for each table.

  25. Brian says:

    HI Andrew,
    Very well written article.

    I have 3 offices all connecting to a single database, on a server at my site.
    Internet is very slow, so am looking to set up a server in each office, with replication. I assume the best way for everyone to have the same data is to use a cluster with master-master replication.
    I will be using ubuntu, running on a VM.
    What is the minimum number of machines you would recommend (3 or 4)?

    • andrew says:

      Using asynchronous replication between the sites is the way to go if the connection between them isn’t fast and reliable. If you want to use MySQL Cluster then the minimum fault tolerant configuration for each site/cluster is 3 machines (the management node should run on a different machine than the data nodes or else it can result in the cluster shutting down in the event of network partitioning).

      Regards, Andrew.

  26. sugun says:

    Hi Andrew,

    Its a great article.

    I have setup a mysql cluster using 7.0.31 release

    I created the table test.assets as given above.

    Here is what I did and the cluster is losing all the data;

    1. Shutdown data node 1
    2. Added the new rows
    3. Made the node 1 up and data is in sync
    4. Now shutdown data node 2
    5. Added new rows;
    6. After 2 minutes, shutdown the entire cluster using shutdown command.
    7. Now when I make all nodes up, there is no data found including our assets table.
    Entire data created is lost. Is that a known issue?

    Thanks
    Sugunakar

    • andrew says:

      sugun, just to check – did you restart the data nodes with the –initial option? If so, that would explain it as this informs the data nodes to throw away all of their data.

      Andrew.

  27. sugun says:

    Thanks Andrew, yeah you are right, I was using the initial option with data nodes.

    Thanks for your help.

    Regards
    sugun

  28. msq says:

    First of All, thanks alot for your effort.
    Secondly, I had setup accordingly but mix with chown -R umysql data command and after restart i m getting this

    120813 13:25:22 [Note] Plugin ‘FEDERATED’ is disabled. 120813 13:25:57 [Note] Starting Cluster Binlog Thread 120813 13:25:57 InnoDB: The InnoDB memory heap is disabled

    • andrew says:

      Hi msq,

      I don’t think that those messages are an issue – if you google them they seem to be harmless (and not connected to the NDB storage engine). Is your setup running?

      Note that for a High Availability solution, the ndb_mgmd(s) shouldn’t be on the same hosts as the data nodes.

      Andrew.

  29. msq says:

    ndb_mgm> show
    Cluster Configuration
    ———————
    [ndbd(NDB)] 2 node(s)
    id=1 @127.0.0.1 (mysql-5.5.25 ndb-7.2.7, Nodegroup: 0, Master)
    id=2 @192.168.1.42 (mysql-5.5.25 ndb-7.2.7, Nodegroup: 0)

    [ndb_mgmd(MGM)] 2 node(s)
    id=101 @192.168.1.40 (mysql-5.5.25 ndb-7.2.7)
    id=102 @192.168.1.42 (mysql-5.5.25 ndb-7.2.7)

    [mysqld(API)] 2 node(s)
    id=51 (not connected, accepting connect from 192.168.1.40)
    id=52 (not connected, accepting connect from 192.168.1.42)

    ndb_mgm> quit
    [mysqlu@Store01p 727]$ bin/mysqld –defaults-file=conf/my.1.conf&
    [1] 5121
    [mysqlu@Store01p 727]$ 120813 16:41:34 [Note] Plugin ‘FEDERATED’ is disabled.

  30. msq says:

    Thanks a lot for your reply.
    I have got through these. basically my mysqld was already running on Node2 and upon shuting it manually got able to start mysqld.

    First: Please tell me in which way we should power off these two nodes (commands wise please).

    secondly, incase of power outage, in whet manner we should start them. (commands please)

    thirdly, I want all of them(ndb_mgm, ndb, mysqld) on both to be auto on. what should I do?

    Fourthly, I have setup a production env based upon your this multi host artilce. that is succesfull and up running but i want to back up their (both) cluster configs and in quick restoreable format. Could u please help me or any step by step doc?

    • andrew says:

      msq,

      mysqlds can be stopped by issuing the command “mysqladmin -u root -h 127.0.0.1 -P3306 shutdown” and can be started with “mysqld –defaults-file=xxxxx”. The rest of the Cluster can be stopped with “ndb_mgm -e shutdown”. You can safely start ndb_mgmds with the –initial option every time but if you do that for data nodes then all of your data will be deleted.

      You can use the infrastructure offered by your OS to automate starting and stopping the processes (for example by placing entries in the /etc/init.d directory on Linux.

      To back up your configuration data, copy your config.ini and my.cnf files. You can use the backup command within ndb_mgm to backup the data held in NDB tables and run regular MySQL backup commands for any other (i.e. InnoDB or MyISAM) tables. You can restore NDB tables using the ndb_restore command. These are documented in the MySQL Cluster documentation.

  31. msq says:

    So nice of you for your answer, Now things are quit clear to me and special thanks for your being in tuch with your this blog which really helping others.

    Well, a bit more is requested about following two points requested.

    secondly, incase of power outage, in what manner we should start them.

    thirdly, I want all of them(ndb_mgm, ndb, mysqld) on both to be auto on. what should I do? I have centos 5.4 x86_64 and mysql Cluster 7.2.7. which entries or files needed to be place?

    atlast btw i have seen three very beautifull kids with u now own ur web. they are very nice.

  32. msq says:

    So nice of you for your answer, Now things are quit clear to me and special thanks for your being in tuch with your this blog which really helping others.

    Well, a bit more is requested about following two points.

    secondly, incase of power outage, in what manner we should start them.

    thirdly, I want all of them(ndb_mgm, ndb, mysqld) on both to be auto on. what should I do? I have centos 5.4 x86_64 and mysql Cluster 7.2.7. which entries or files needed to be place?

    atlast btw i have seen three very beautifull kids with u now own ur web. they are very nice.

  33. msq says:

    One another issue is.

    I hv created a db “abc” on Node A using
    create database abc; and on Node B db created automatically but when i restores backup on it using bin/mysql -u root -P 3306 -p abc < /home/myuser/abcDump.sql, it restores all tables to Node A including data inside it but no tables found on Node B.
    should i use mdbcluster with restore command or what syntax?

    Sorry for disturbing u again

  34. sugun says:

    Hi andrew,

    I configured MGMT node and mysqld on single host. Data nodes are on two diff machines.
    MGMT and data nodes are doing fine. I can get their status via ndb_mgm. But mysqld is not coming up. My steps are listed below:

    on mgmt box, I just the scripts/mysql_install_db script and then configued a my.conf file.

    scripts/mysql_install_db –basedir=/home/sugun/mysql/7_0_31 –datadir=/home/sugun/mysql/7_0_31/data

    config.ini:
    ————–
    [ndbd default]
    noofreplicas=2

    [ndbd]
    hostname=192.168.56.2
    Nodeid=1

    [ndbd]
    hostname=192.168.56.3
    Nodeid=2

    [ndb_mgmd]
    Nodeid = 106
    hostname=192.168.56.7

    [mysqld]
    Nodeid=55
    hostname=192.168.56.7

    My.conf file contents:
    ———
    [mysqld]
    ndb-nodeid=55
    ndbcluster
    datadir=/home/sugun/mysql/7_0_31/data
    basedir=/home/sugun/mysql/7_0_31
    port=3306
    server-id=55
    log-bin

    When started the mysqld on its failing to start. Could you please help me out

    $ bin/mysqld –defaults-file=conf/my.conf&

    Below is the error message:

    [sugun@ndb_mgr1 7_0_31]$ 120816 7:27:51 [Warning] No argument was provided to –log-bin, and –log-bin-index was not used; so replication may break when this MySQL server acts as a master and has his hostname changed!! Please use ‘–log-bin=ndb_mgr1-bin’ to avoid this problem.
    120816 7:27:51 [Note] Plugin ‘FEDERATED’ is disabled.
    bin/mysqld: Table ‘mysql.plugin’ doesn’t exist
    120816 7:27:51 [ERROR] Can’t open the mysql.plugin table. Please run mysql_upgrade to create it.
    120816 7:27:51 InnoDB: Initializing buffer pool, size = 8.0M
    120816 7:27:51 InnoDB: Completed initialization of buffer pool
    InnoDB: Log scan progressed past the checkpoint lsn 0 37356
    120816 7:27:51 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: Doing recovery: scanned up to log sequence number 0 44233
    120816 7:27:51 InnoDB: Starting an apply batch of log records to the database…
    InnoDB: Progress in percents: 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
    InnoDB: Apply batch completed
    120816 7:27:52 InnoDB: Started; log sequence number 0 44233
    120816 7:27:52 [Note] NDB: NodeID is 55, management server ‘192.168.56.7:1186′
    120816 7:27:52 [Note] NDB[0]: NodeID: 55, all storage nodes connected
    120816 7:27:52 [Note] Starting Cluster Binlog Thread
    120816 7:27:52 [Note] Recovering after a crash using ndb_mgr1-bin
    120816 7:27:52 [Note] Starting crash recovery…
    120816 7:27:52 [Note] Crash recovery finished.
    120816 7:27:52 [ERROR] Fatal error: Can’t open and lock privilege tables: Table ‘mysql.host’ doesn’t exist

    Thanks
    Sugun

    • andrew says:

      Segun,

      1st thing – if at all possible use a newer version of MySQL (7.2).

      2nd thing – make sure that you use the Cluster basedir for mysql_install_db and then the mysqld from that basedir (rather than a non-Cluster mysqld or one that came with a different version of Cluster).

      Andrew.

  35. sugun says:

    MSQ,

    Please check the backup file and ensure that each table is having an extension like engine=ndbcluster.

    If you open your backup file, you will see lot of lines as given below:
    create table xxxx engine=’InnoDB';

    You have to change that entry to engine=’ndb';
    Then all tables will be created in the cluster.

  36. msq says:

    I hv created a db “abc” on Node A using
    create database abc; and on Node B db created automatically but when i restores backup on it using bin/mysql -u root -P 3306 -p abc < /home/myuser/abcDump.sql, it restores all tables to Node A including data inside it but no tables found on Node B.
    should i use mdbcluster with restore command or what syntax?

    • andrew says:

      msq – for MySQL Cluster, your best bet for backups is to use the online backup command within ndb_mgm and the retire using ndb_restore (note that you’ll need an unused [ndbpai] or [mysqld] section in your config.ini file for ndb_restore to connect to.

      Andrew.

  37. msq says:

    Thank you very much SUGUN AND ANDREW i have successfully rstored the databases on one and get on the second node.

    There is one issue, i have setup the cluster accord to this article but when one of my mgm node got down (which show master in normal ruuning) the other one could not get online untill i manual online the master.. IS it possible that one will run in case of down of other one automatically

  38. msq says:

    Is this possible to have one node available in case of down of other node automatically

  39. fairsimple says:

    [root@Store01p 727i686]# bin/ndb_mgm -e show
    Connected to Management Server at: localhost:1186
    Cluster Configuration
    ———————
    [ndbd(NDB)] 2 node(s)
    id=1 @127.0.0.1 (mysql-5.5.25 ndb-7.2.7, starting, Nodegroup: 0)
    id=2 @192.168.1.42 (mysql-5.5.25 ndb-7.2.7, starting, Nodegroup: 0)

    [ndb_mgmd(MGM)] 2 node(s)
    id=101 @192.168.1.41 (mysql-5.5.25 ndb-7.2.7)
    id=102 @192.168.1.42 (mysql-5.5.25 ndb-7.2.7)

    [mysqld(API)] 2 node(s)
    id=51 (not connected, accepting connect from 192.168.1.41)
    id=52 (not connected, accepting connect from 192.168.1.42)

    wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww
    1:
    Please tell y this is hang on starting…
    I have checked it by other user aswell but its still ??

  40. fairsimple says:

    Please help
    When ever I issue command bin/mysqld –defaults-file=conf/my.2.conf&

    I Got This output—
    Neither mdbd is going out of “starting” nor this response understandable
    ==========================

    121124 4:27:07 [Warning] No argument was provided to –log-bin, and –log-bin-index was not used; so replication may break when this MySQL server acts as a master and has his hostname changed!! Please use ‘–log-b in=Store02p-bin’ to avoid this problem.
    121124 4:27:07 [Note] Plugin ‘FEDERATED’ is disabled.
    121124 4:27:07 InnoDB: The InnoDB memory heap is disabled
    121124 4:27:07 InnoDB: Mutexes and rw_locks use InnoDB’s own implementation
    121124 4:27:07 InnoDB: Compressed tables use zlib 1.2.3
    121124 4:27:07 InnoDB: Using Linux native AIO
    121124 4:27:07 InnoDB: Initializing buffer pool, size = 128.0M
    121124 4:27:07 InnoDB: Completed initialization of buffer pool
    121124 4:27:07 InnoDB: highest supported file format is Barracuda.
    121124 4:27:07 InnoDB: Waiting for the background threads to start
    121124 4:27:08 InnoDB: 1.1.8 started; log sequence number 1595675
    121124 4:27:43 [Note] Starting Cluster Binlog Thread
    121124 4:27:43 [Note] Recovering after a crash using Store02p-bin
    121124 4:27:43 [Note] Starting crash recovery…
    121124 4:27:43 [Note] Crash recovery finished.
    121124 4:27:43 [Note] Server hostname (bind-address): ‘0.0.0.0’; port: 5000
    121124 4:27:43 [Note] – ‘0.0.0.0’ resolves to ‘0.0.0.0’;
    121124 4:27:43 [Note] Server socket created on IP: ‘0.0.0.0’.
    121124 4:27:43 [Note] Event Scheduler: Loaded 0 events
    121124 4:27:43 [Note] bin/mysqld: ready for connections.
    Version: ‘5.5.25a-ndb-7.2.7-gpl-log’ socket: ‘/tmp/mysql.sock’ port: 5000 MyS QL Cluster Community Server (GPL)
    [admin@Store02p 727i686]$ 121124 4:28:13 [Warning] NDB : Tables not available after 30 seconds. Consider increasing –ndb-wait-setup value

    • andrew says:

      fairsimple – you need to figure out why the data nodes aren’t starting correctly. Check the cluster logs – should be in the ndb_mgmd’s datadir and the ndbds’s logs – should be in their datadirs.

  41. fairsimple says:

    Inwhich dir do u think in following:
    wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww

    Connected to Management Server at: localhost:1186
    Cluster Configuration
    ———————
    [ndbd(NDB)] 2 node(s)
    id=1 @127.0.0.1 (mysql-5.5.25 ndb-7.2.7, starting, Nodegroup: 0)
    id=2 @192.168.1.42 (mysql-5.5.25 ndb-7.2.7, starting, Nodegroup: 0)

    [ndb_mgmd(MGM)] 2 node(s)
    id=101 @192.168.1.41 (mysql-5.5.25 ndb-7.2.7)
    id=102 @192.168.1.42 (mysql-5.5.25 ndb-7.2.7)

    [mysqld(API)] 2 node(s)
    id=51 (not connected, accepting connect from 192.168.1.41)
    id=52 (not connected, accepting connect from 192.168.1.42)

    [root@Store01p 727i686]# ls -la
    total 544
    drwxrwxrwx 15 admin root 4096 Nov 24 06:33 .
    drwxrwxrwx 3 admin root 4096 Nov 24 02:22 ..
    drwxr-xr-x 2 admin root 4096 Nov 24 04:55 bin
    drwxr-xr-x 2 admin root 4096 Nov 24 06:34 conf
    -rw-r–r– 1 admin root 17987 Jul 13 05:27 COPYING
    drwxr-xr-x 6 admin root 4096 Nov 24 06:30 data
    drwxr-xr-x 2 admin root 4096 Nov 24 02:12 docs
    drwxr-xr-x 4 admin root 4096 Nov 24 02:12 include
    -rw-r–r– 1 admin root 7604 Jul 13 05:27 INSTALL-BINARY
    drwxr-xr-x 3 admin root 4096 Nov 24 02:11 lib
    drwxr-xr-x 4 admin root 4096 Nov 24 02:12 man
    drwxr-xr-x 10 admin root 4096 Nov 24 02:12 mysql-test
    -rw-r–r– 1 admin root 416548 Nov 24 06:51 ndb_101_cluster.log
    -rw-r–r– 1 admin root 536 Nov 24 06:34 ndb_101_out.log
    -rw-r–r– 1 root root 4 Nov 24 06:33 ndb_101.pid
    drwxr-x— 2 admin root 4096 Nov 24 02:38 ndb_1_fs
    -rw-r–r– 1 admin root 26065 Nov 24 06:35 ndb_1_out.log
    -rw-r–r– 1 admin root 4 Nov 24 06:35 ndb_1.pid
    -rw-r–r– 1 admin root 2552 Jul 13 05:27 README
    drwxr-xr-x 2 admin root 4096 Nov 24 02:12 scripts
    drwxr-xr-x 29 admin root 4096 Nov 24 02:12 share
    drwxr-xr-x 4 admin root 4096 Nov 24 02:11 sql-bench
    drwxr-xr-x 2 admin root 4096 Nov 24 02:12 support-files

  42. fairsimple says:

    Secondly,
    1:
    Why its showning me “127.0.0.1” ?

    id=1 @127.0.0.1 (mysql-5.5.25 ndb-7.2.7, starting, Nodegroup: 0)

    2:
    Do I have to setup IP in etc/hosts ?

  43. fairsimple says:

    Please help Its urgent—- I have been working with it for 4 days—-or if u could share skype id for some time so we can talk

    Here are the logs on cluster on Node A same are on Node B
    wwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww

    2012-11-24 07:49:37 [MgmtSrvr] INFO — Node 1: Initial start, waiting for 2 to connect, nodes [ all: 1 and 2 connected: 1 no-wait: ]
    2012-11-24 07:49:39 [MgmtSrvr] INFO — Node 2: Initial start, waiting for 1 to connect, nodes [ all: 1 and 2 connected: 2 no-wait: ]
    2012-11-24 07:49:40 [MgmtSrvr] INFO — Node 1: Initial start, waiting for 2 to connect, nodes [ all: 1 and 2 connected: 1 no-wait: ]
    2012-11-24 07:49:42 [MgmtSrvr] INFO — Node 2: Initial start, waiting for 1 to connect, nodes [ all: 1 and 2 connected: 2 no-wait: ]
    2012-11-24 07:49:43 [MgmtSrvr] INFO — Node 1: Initial start, waiting for 2 to connect, nodes [ all: 1 and 2 connected: 1 no-wait: ]
    2012-11-24 07:49:45 [MgmtSrvr] INFO — Node 2: Initial start, waiting for 1 to connect, nodes [ all: 1 and 2 connected: 2 no-wait: ]
    2012-11-24 07:49:46 [MgmtSrvr] INFO — Node 1: Initial start, waiting for 2 to connect, nodes [ all: 1 and 2 connected: 1 no-wait: ]

  44. fairsimple says:

    Still Same Output
    wwwwwwwwwwwwwwwwwwwwwww

    Connected to Management Server at: localhost:1186
    Cluster Configuration
    ———————
    [ndbd(NDB)] 2 node(s)
    id=1 @192.168.1.41 (mysql-5.5.25 ndb-7.2.7, starting, Nodegroup: 0)
    id=2 @192.168.1.42 (mysql-5.5.25 ndb-7.2.7, starting, Nodegroup: 0)

    [ndb_mgmd(MGM)] 2 node(s)
    id=101 @192.168.1.41 (mysql-5.5.25 ndb-7.2.7)
    id=102 @192.168.1.42 (mysql-5.5.25 ndb-7.2.7)

    [mysqld(API)] 2 node(s)
    id=51 (not connected, accepting connect from 192.168.1.41)
    id=52 (not connected, accepting connect from 192.168.1.42)

  45. fairsimple says:

    No need of getting tension Andrew:;;;

    I have solved it my self and finally got through it Now the things are working fine…

    Its some where firewall issue though I have allowed 1186 and 5000 3306 but it wasnt working..
    Just stoped the fw and its connected…Is there any other port hidden which should be permitted?

  46. fairsimple says:

    do u refer any step by step cluster administration tutorials?

    Any Db conversion tutorials?

  47. fairsimple says:

    Specially:

    If one have mgm server on third node should he use that mgm’s Ip to auto failover and HA?

  48. fairsimple says:

    Hi Andrew

    What about HA in your this article or if someone wants to have auto failover and have mgmd on third node which IP or setts he should do for web apps to use HA of mysql cluster

  49. fairsimple says:

    do u have any idea?

  50. fairsimple says:

    Hi
    What about HA in your this article or if someone wants to have auto failover and have mgmd on third node which IP or setts he should do for web apps to use HA of mysql cluster

  51. p0is0n says:

    Hi,
    having read this tutorial, I wonder why putting three nodes (mgmt,db,sql) on a single host in two host cluster is so problematic in terms of HA? In fact, we have all nodes doubled.Is it any technical reason that mgmt node cannot coexist with db node on the same host “Note that the management node consumes very few resources and so can share that host with other functions/applications (e.g. SQL Server nodes but not data nodes).” so that it affects HA? I have powerful-enough machine to host all of them.All FAQs simply are simply reapeating that one needs at least 4 hosts for full redundancy but don’t explain why..Will be grateful if someone could shed some light on it.
    Thanks in advance.

  52. p0is0n says:

    Andrew,
    thanks for help.
    From what I understood from this example, colocation of mgmt and data nodes implies that in case of a failure of the entire host with active arbitrator, service will be lost because it will end up with inactive arbitrator on the remaining node. Does that mean that failure of the arbitrator (that is:mgmd) does not effect in electing a new one?Not sure what is the difference between this scenario and another -when we have 2 hosts with mgmt nodes and the active arbitrator host fails entirely. I guess in both cases the new arbitrator election should happen. Pls advice. Thanks

    • andrew says:

      p0i0n,

      if you lost the host running the arbitrator and half of the data nodes then that doesn’t leave you with a quorum to elect a new arbitrator and so the only safe thing to do is shut down.

      There should be no problem running the ndb_mgmd on Windows and everything else on Linux.

      Andrew.

  53. p0is0n says:

    And one more thing – is it possible to have mysql+db nodes on linux hosts and management nodes on windows hosts? Will it work flawlessly and is supported configuration?Unfortunately, if I had to spare some resources for managements on external hosts, these would have to be windows boxes :/

  54. Nick Shaw says:

    Hi Andrew,

    I’ve run into an issue in our environment, we are using mysql cluster manager to manage our data nodes.

    It seems that the data nodes (running ndbmtd) assign random local ports, this is causing issues as our database tier is firewalled. Is there a way to force the multi threaded engine to specific ports?

    Nick

  55. fairsimply says:

    i hv setup a two node cluster using ur article and migrated 04 database of volume 300MB each (each Server memory hv 8GB ) but hve two questions

    1: each time I want to make any update in database its repsonce is deadly slow. y is this and how can overcome this?

    2: tacking backup using “start backup” in ndb_mgm> but what if we have to restore some of files from that backup? how can i do this?

    • andrew says:

      fairsimply,

      as you’d expect, there are many reasons for why a database operation may be slow – depending on what your application is doing, what the schema looks like and how the database is configured. A good place to start would be this performance white paper.

      Restores are performed using the ndb_restore command standalone command and not part of ndb_mgm.

      Andrew.

  56. Hoggins! says:

    Hello,

    Thanks to this post, I successfully managed to have a working MySQL cluster, that’s great !
    I now have a little question : I have two SQL nodes, so data can be accessed independently from mysql-1 or mysql-2.

    Do you know if any MySQL connector (I’m thinking of PHP, for example) is able to handle two or more MySQL servers ?

    I would like my application to be able to transparently load-balance its connections to MySQL, and also switch to the second MySQL node if the first fails.

    Is it included in the MySQL connectors, so I would only have to specify something like : connect=mysql-1,mysql-2, or do I have to implement it myself ?

  57. Sire says:

    What ethernet links one would need to deploy 2 node ( 2 x dbd/2x sqld, that is: 1xdbd/1xmysqld on the same host) in master-master/master-slave config when used in CRM system (mostly textual data) in 25/50/100 concurrent users scenario?
    Would 100Mbps for 25 users and 1000Mbps for 50/1000 users respectively be enough or should I forget the whole idea withouth 10Gbps link?
    Could someone tell from their experience?
    Thanks a lot.

    • andrew says:

      Sire,

      of course it’s going to be dependent on the application load but on the face of it the number of users you specify seems pretty low and so I think you could start with the networking you propose and see how it performs.

      Andrew.

  58. Sire says:

    Andrew,
    ok, that is understandable and before deployment one cannot really be precise with the estimation, however I can say that data transfers would be small text chunks, so probably equal to or even less than typical “web usage” scenario /but no flash or other heavy objects-only graphics will probably be those of GUI/.
    However, in terms of cluster consistency- is there any minimum interconnect speed/max latency that breaks it or makes it? Should 1Gbps suffice for 50-100 concurrent users?
    While 1Gbps infrastructure has pretty modest costs, a need to upgrade to 10Gbps may be costly.

    • andrew says:

      Sire,
      The speed of the connection required is dependent on the volume of data that’s being read and (especially) written. As you say, your requirements seem modest and so 1G may well be enough. Regarding latency of the network, the most sensitive area is the connection between data nodes – we recommend that you aim to have this less than 20ms (should be easy for a LAN, the reccommendation is really aimed as multi-data-center Clusters) but even then you can adjust the heartbeat settings to make the Cluster more tolerant of higher latencies.

      Andrew.

  59. Achal says:

    Hi Andrew,

    I am facing a problem while starting mysqld using
    bin/mysqld –defaults-file=conf/my.1.conf&

    OUTPUT goes like:
    131013 5:24:57 [ERROR] Fatal error: Please read “Security” section of the manual to find out how to run mysqld as root!

    131013 5:24:57 [ERROR] Aborting

    131013 5:24:57 [Note] bin/mysqld: Shutdown complete

    Please suggest I will be very thankful to you.

    Thanks,
    Achal

    • andrew says:

      Vijay,

      it looks like you’re attempting to run the mysqld while logged in as root – that’s blocked for security reasons, try running it as a normal user.

      Andrew.

  60. Achal says:

    hi Andrew,

    as u suggested in previous post, this time i am doing this with normal user but facing errors from the very starting,

    [billy@cls1 mysql]$ scripts/mysql_install_db –basedir=/home/billy/mysql/ –datadir=/home/billy/mysql/data/
    chown: changing ownership of `/home/billy/mysql/data/': Operation not permitted
    Cannot change ownership of the database directories to the ‘mysql’
    user. Check that you have the necessary permissions and try again.

    chmod mysql:mysql -R mysql done as i have renamed my extracted folder to mysql.

    Please help me,
    eagerly waiting for your positive responce.

    Thanks,
    Achal

    • andrew says:

      Hi Achal,

      where it’s neccessary to grant permissions, you need to be logged in as a user able to grant those permissions. Where you’re trying to run chmod, chown or similar commands you need the required authority – for example run them as root. The only root restricion is that when you run mysqld, you must *not* be the root user.

      Regards, Andrew.

  61. Achal says:

    sure Andrew, will try the same and if error occurs will update you and

    Thanks for helping me.

    Achal

  62. Marcio Oliveira says:

    Hello I have an environment with 2 NDB MGM and 2 SQL when I start mysql does not connect at MGM in the log that failed to allocate nodeid is api at 10.139.139.94. Returned error: ‘No free node id found for mysqld (API). the ndbd starts and connects to MGM without error. ‘So that mysqld does not connect.

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