[jira] [Commented] (CASSANDRA-7034) commitlog files are 32MB in size, even with a 64bit OS and jvm

["Donald Smith (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-7034?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13969886#comment-13969886 ] 

Donald Smith commented on CASSANDRA-7034:
-----------------------------------------

Benedict, I'm aware that *commitlog_total_space_in_mb* has that purpose.  What I'm raising is the issue that this comment in cassandra,yaml is now wrong: "the default size is 32 on 32-bit JVMs, and 1024 on 64-bit JVMs.."  That's no longer being enforced.

> commitlog files are 32MB in size, even with a 64bit  OS and jvm
> ---------------------------------------------------------------
>
>                 Key: CASSANDRA-7034
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7034
>             Project: Cassandra
>          Issue Type: Bug
>            Reporter: Donald Smith
>
> We did a rpm install of cassandra 2.0.6 on CentOS 6.4 running 
> {noformat}
> > java -version
> Java(TM) SE Runtime Environment (build 1.7.0_40-b43)
> Java HotSpot(TM) 64-Bit Server VM (build 24.0-b56, mixed mode)
> {noformat}
> That is the version of java CassandraDaemon is using.
> We used the default setting (None) in cassandra.yaml for commitlog_total_space_in_mb:
> {noformat}
> # Total space to use for commitlogs.  Since commitlog segments are
> # mmapped, and hence use up address space, the default size is 32
> # on 32-bit JVMs, and 1024 on 64-bit JVMs.
> #
> # If space gets above this value (it will round up to the next nearest
> # segment multiple), Cassandra will flush every dirty CF in the oldest
> # segment and remove it.  So a small total commitlog space will tend
> # to cause more flush activity on less-active columnfamilies.
> # commitlog_total_space_in_mb: 4096
> {noformat}
> But our commitlog files are 32MB in size, not 1024MB.
> OpsCenter confirms that commitlog_total_space_in_mb is None.
> I don't think the problem is in cassandra-env.sh, because when I run it manually and echo the  values of the version variables I get:
> {noformat}
> jvmver=1.7.0_40
> JVM_VERSION=1.7.0
> JVM_ARCH=64-Bit
> {noformat}



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