Error on data node startup in MySQL-cluster Running a 24 core server (with HT enabled) I tried increasing MaxNoOfExecutionThreads to 24 to perform some benchmarks and got the following error:

2013-02-27 11:21:44 [ndbd] INFO     -- Trying to start 12 LQH workers with only 4 log parts, try initial node restart to be able to use more LQH workers.

Here are options from config.ini I find relevant:

NoOfFragmentLogFiles=64

FragmentLogFileSize=128M

It seems that Redo Log file number (not fragment) is always four and they are created in D9-D11 directory on the FS. I haven't been able to find a parameter to change this.

Version running is: 5.5.29-ndb-7.2.10

Any help or experience is welcome.

EDIT - solution:
The following option defines the number of Redo log files - NoOfFragmentLogParts

After setting it to 12, you get D8-D19 for Redo Logs and 24 as MaxNoOfExecutionThreads works fine.
You can try and set


[NDBD DEFAULT]
...

NoOfFragmentLogParts=12
...


http://dev.mysql.com/doc/refman/5.5/en/mysql-cluster-ndbd-definition.html#ndbparam-ndbmtd-nooffragmentlogparts

Then restart all nodes with --initial

Best regards

Johan Andersson

Severalnines AB