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https://issues.apache.org/jira/browse/CASSANDRA-1469?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12908946#action_12908946
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Jonathan Ellis commented on CASSANDRA-1469:
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wouldn't it be cleaner to have something like
# logic to compute ADAPTIVE_HEAP_SIZE
MAX_HEAP_SIZE="$ADAPTIVE_HEAP_SIZE" # override to force specific heap size,
e.g. "6GB"
also, can you update the debian script too?
> adaptive default heap size
> --------------------------
>
> Key: CASSANDRA-1469
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1469
> Project: Cassandra
> Issue Type: New Feature
> Components: Packaging
> Reporter: Jonathan Ellis
> Assignee: Brandon Williams
> Fix For: 0.7.0
>
> Attachments: 0001_adaptively_determine_heap_size.txt
>
>
> Cassandra comes out of the box with very conservative defaults, especially in
> -Xmx and memtable sizes, which leads to complaints of poor performance or
> even OOM conditions under heavy load. But changing these to be aggressive
> can cause the same problem: most servers enable swap out of the box, so
> asking for a 4GB or 8GB heap could allocate happily but also cause problems
> when it starts paging.
> Proposed solution is to update the start script to set Xmx to half of system
> ram ("free -m | awk '/Mem:/ {print $2}'"). Memtable defaults will have to be
> handled by Java, but we can do that based on heap size (Runtime.maxMemory).
> An alternative suggestion was to provide "small", "medium", "large"
> configurations, but this plays poorly with rpm and deb packages. I think the
> adaptive approach is more promising.
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