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From Apache Wiki <wikidi...@apache.org>
Subject [Cassandra Wiki] Update of "PerformanceTuning" by FlipKromer
Date Tue, 31 Aug 2010 03:49:57 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Cassandra Wiki" for change notification.

The "PerformanceTuning" page has been changed by FlipKromer.
http://wiki.apache.org/cassandra/PerformanceTuning?action=diff&rev1=5&rev2=6

--------------------------------------------------

+ Be sure to review the page on [[MemtableThresholds|Memtable Thresholds]] -- several important
configuration and system settings are described there.
+ 
+ === Lessen overall system impact of Compactions ===
  To lower compaction priority (thus reducing its impact on the rest of the system, and making
it take longer), add these options to cassandra.in.sh in 0.6.3 or later:
  
  {{{
@@ -7, +10 @@

  -XX:ThreadPriorityPolicy=42 \
  -Dcassandra.compaction.priority=1 \
  }}}
- 
- Useful JVM options:
+ === Useful JVM options ===
- 
  {{{
  -XX:+UseCompressedOops # enables compressed references, reducing memory overhead on 64bit
JVMs
  }}}
- 
  See http://wikis.sun.com/display/HotSpotInternals/CompressedOops and http://publib.boulder.ibm.com/infocenter/javasdk/v6r0/topic/com.ibm.java.doc.diagnostics.60/diag/understanding/mm_compressed_references.html
for discussion on the Sun and IBM JVMs, respectively.
  
  Compressed references (aka OOPs = ordinary object pointers) are not stable for Sun JVM versions
before 6u19.
  
+ == System Settings ==
  todo: describe how top, iostat -x, and JMX stats can help you see what is making things
slow
  
  For starters, see "[[http://spyced.blogspot.com/2010/01/linux-performance-basics.html|Linux
Performance Basics for Cassandra]]".
  
- Also review the page on [[MemtableThresholds|Memtable Thresholds]].
- 

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