Optimizing Memory Usage

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Zenoss 4 uses several new technologies including RabbitMQ and some Java-based applications, which can consume quite a bit of memory. The minimum recommended amount of RAM for a Zenoss 4.x install is 8GB.

This section will document some steps you can use to make Zenoss more memory-efficient for deployments with relatively low numbers of managed devices, where extreme scalability is not a concern.


Zenoss Core 4 uses MySQL.

The commercial version of Zenoss uses zends. Zends is a commercially-licensed version of MySQL that is included with Zenoss Service Dynamics. By default, it is tuned to handle up to 2000 devices. For smaller installations, the pool and cache sizes may be a bit high.

To change settings for MySQL, edit /opt/zenoss/etc/my.cnf (or /opt/zends/etc/zends.conf if you are using the commercial version.) Change innodb_buffer_pool_size to a smaller value, such as 256M. You can also lower the other sizes accordingly. Suggested minimal configuration:

max_allowed_packet = 64M
innodb_buffer_pool_size = 256M
# log file size should be 25% of of buffer pool size
innodb_log_file_size = 64M
innodb_additional_mem_pool_size = 16M
innodb_log_buffer_size = 4M
innodb_fast_shutdown = 1
innodb_flush_log_at_trx_commit = 2

max_allowed_packet = 64M

You will need to edit this file as root. After making changes, perform the following steps:

# /etc/init.d/mysql restart

For the commercial version, you will want to use the zends initscript:

# /etc/init.d/zends stop
# rm /etc/zends/data/ib_logfile*
# /etc/init.d/zends start


zeneventserver is a new Java-based event server for Zenoss. By default, it will allow the Java heap to grow to 1/4 of the available system memory with a 64-bit JVM. This can be modified by editing the /home/zenoss/.bashrc file to add a -Xmx512m option to the default JVM arguments, as follows:

$ export DEFAULT_ZEP_JVM_ARGS="-server -Xmx512m"

Type zeneventserver restart as the zenoss user to apply these new settings.

Stopping Daemons

Zenoss uses ZenPacks to extend functionality of the core product, and also includes some additional daemons that you may not need. To turn extra daemons off, perform the following steps:

$ touch /opt/zenoss/etc/DAEMONS_TXT_ONLY

Then create a file called /opt/zenoss/etc/daemons.txt that contains something like this:


The list above is a list of all daemons that start when you run zenoss restart as the zenoss user. I've commented out the ones I don't want by appending a #.