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From:Andrew Morgan Date:May 25 2012 12:31pm
Subject:RE: Starting a single ndbd instance spawns two processes
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Hi Róbert,

 Each data node is actually made up of 2 ndbd processes - the main one and its angel. If
you've set STOPONERROR to false then the agent will automatically restart the main ndbd
process should it die.

Regards, Andrew.

-----Original Message-----
From: Róbert Kohányi [mailto:kohanyi.robert@stripped] 
Sent: 24 May 2012 12:54
To: cluster@stripped
Subject: Starting a single ndbd instance spawns two processes

I'm experimenting with a basic cluster configuration inside Virtual Box (running Ubuntu
10.04 LTS) using MySQL distrib mysql-5.5.22 ndb-7.2.6, for linux2.6 (x86_64). (I've
downloaded the latest generic Linux binary from the main website.)

I've successfully set up a working cluster inside a single VM (obviously just for
testing), which contains two ndb_mgmd, two ndbd and two mysqld nodes. (In production I
plan to run these on two or more

I've posted my cluster configuration[1] and the outline of how I start my processes[2] to

Everything works fine, but I've noticed that there are four ndbd processes running on the
I've posted some info on these four processes[3] to pastebin too.

I've noticed that each two processes are in a parent-child relationship, and I figure that
this *could* be normal, but I'm not sure. Anyone has an explanation why is this happening?
(I didn't find info on this particular matter in the MySQL 5.5 Reference Manual - not yet
at least.)

Thanks in advance!



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Starting a single ndbd instance spawns two processesRóbert Kohányi24 May
  • RE: Starting a single ndbd instance spawns two processesAndrew Morgan25 May