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MySQL Cluster Overview

This is a chaotic collection of my MySQL Cluster experience...

* config.ini template	* MySQL Cluster restore	* Monitoring (cmon)
* my.cnf template	* Skript for converting tables to NDB	* Configuration Tool
* Skript from Bernd	* MySQL Cluster memory sizing	* General Rules and/or experience

config.ini template

A generic config.ini to start with. It is pretty much what MySQL Cluster experts recommend right now...

my.cnf template

A generic my.cnf to start with MySQL Cluster.

Genral rules and/or experience

MySQL Cluster v5.0

Avoid ALTER TABLE in MySQL Cluster.
It needs 2 x the RAM of a table (memory is reclaimed only after a node restart).
Do ALTER TABLE <table> ENGINE=MyISAM; instead, then the changes and then alter back to the cluster.
DROP/TRUCATE reclaims pages.
UPDATE/INSERT/DELETE causes memory de-fragmentation (same symptoms like a memory leak) ⇒ requires a node restart from time to time.
For production use is still and only v5.0 (exception CGE)!

MySQL Cluster v5.1

On disk table ⇒ is stable now.
Parallel node recovery is not yet implemented in v5.1 ⇒ maybe 5.2/6.0?
Partitioning does not work from the SQL interface (mysqld) but from the NDB-API.
No more memory de-fragmentation is done (see above).
Cluster to MySQL replication is still buggy! But should work.
Cluster to Cluster replication is stable.
In Cluster replication:

binlog_cache_size    = TimeBetweenGlobalCheckpoints/1000 (default 2000)
(default 32 kbyte)     * total traffic (Mbyte/s) (for example 5 Mbyte/s)
                     = 2000 ms / 1000 ms/s * 5 Mbyte/s
                     ≌ 10 Mybte

pdflush(kswapd) flushes every 5 seconds pages to disk ⇒ Causes troubles with cluster.
The kernel parameters vm.page-cluster and vm.lower-zone-protection (later one does not exist on my maybe non-NUMA system) can help:

# cat /proc/sys/vm/lower_zone_protection
# cat /proc/meminfo
# sysctl vm | egrep 'page-cluster|lower-zone-protection'

For MySQL Cluster on AMD Hardware set NUMA to OFF in BIOS! ⇒ Preferred hardware: Intel!
File system: Use ext3 or XFS.

Literature

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