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http://jira.amdatu.org/jira/browse/AMDATUCASSANDRA-114?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=11789#comment-11789
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Ivo Ladage - van Doorn edited comment on AMDATUCASSANDRA-114 at 10/19/11 2:32
PM:
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Further analyzed this issue focussing on what is actually going wrong. This
page describes pretty well what the 'liveratio' warning is about:
http://thelastpickle.com/2011/05/04/How-are-Memtables-measured/
In Cassandra 0.8 a new way was introduced to determine when a memtable should
be flushed to disk, called 'memtable_total_space_in_mb'. Although this setting
is uncommented in the cassandra.yaml, this approach is used by default. The new
approach uses the Java agent as it needs to calculate the actual size of all
objects stored in the memtable, before flushing it to disk. When the Java agent
is not available, it fails to detect the liveratio and uses the default factor
10 instead. As a result, memtables may be flushed to SSTables to soon or not
soon enough.
In 0.8 this approach is the default, but the 'old' 0.7 way can be turned on by
changing the memtable_total_space_in_mb setting to 0. This will be the short
term solution. We still need to think of a final solution, as this new approach
probably will be the only supported approach in the future (though 1.0 still
supported the old way).
was (Author: ivol):
Further analyzed this issue focussing on what is actually going wrong. This
page describes pretty well what the 'liveratio' warning is about:
http://thelastpickle.com/2011/05/04/How-are-Memtables-measured/
In Cassandra 0.8 a new way was introduced to determine when a memtable should
be flushed to disk, called 'memtable_total_space_in_mb'. Although this setting
is uncommented in the cassandra.yaml, this approach is used by default. The new
approach uses the Java agent as it needs to calculate the actual size of all
objects stored in the memtable, before flushing it to disk. When the Java agent
is not available, it fails to detect the liveratio and uses the default factor
10 instead.
> Lot of "MemoryMeter uninitialized" WARNING messages when starting Cassandra
> on Linux
> ------------------------------------------------------------------------------------
>
> Key: AMDATUCASSANDRA-114
> URL: http://jira.amdatu.org/jira/browse/AMDATUCASSANDRA-114
> Project: Amdatu Cassandra
> Issue Type: Bug
> Components: Cassandra daemon
> Affects Versions: 0.2.0
> Reporter: Ivo Ladage - van Doorn
> Fix For: 0.2.1
>
>
> This message appears a lot when Cassandra is started:
> WARNING: MemoryMeter uninitialized (jamm not specified as java agent);
> assuming liveRatio of 10.0. Usually this means cassandra-env.sh disabled
> jamm because you are using a buggy JRE; upgrade to the Sun JRE instead
> [org.amdatu.core.loghandler]
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