reddit/config/cassandra/storage-conf.xml

<Storage>
  <!--======================================================================-->
  <!-- Basic Configuration                                                  -->
  <!--======================================================================-->

  <ClusterName>reddit</ClusterName>

  <AutoBootstrap>false</AutoBootstrap>
  <HintedHandoffEnabled>true</HintedHandoffEnabled>

  <Keyspaces>
    <Keyspace Name="permacache">
      <ColumnFamily CompareWith="BytesType" Name="permacache" RowsCached="3000000" />

      <ReplicaPlacementStrategy>org.apache.cassandra.locator.RackUnawareStrategy</ReplicaPlacementStrategy>
      <ReplicationFactor>3</ReplicationFactor>
      <EndPointSnitch>org.apache.cassandra.locator.EndPointSnitch</EndPointSnitch>
    </Keyspace>

    <Keyspace Name="urls">
      <ColumnFamily CompareWith="UTF8Type" Name="urls" />

      <ReplicaPlacementStrategy>org.apache.cassandra.locator.RackUnawareStrategy</ReplicaPlacementStrategy>
      <ReplicationFactor>3</ReplicationFactor>
      <EndPointSnitch>org.apache.cassandra.locator.EndPointSnitch</EndPointSnitch>
    </Keyspace>

    <Keyspace Name="reddit">
      <!-- Relations -->
      <ColumnFamily CompareWith="UTF8Type" Name="LinkVote" />
      <ColumnFamily CompareWith="UTF8Type" Name="CommentVote" />

      <!-- Views -->
      <ColumnFamily CompareWith="UTF8Type" Name="VotesByLink" />

      <ReplicaPlacementStrategy>org.apache.cassandra.locator.RackUnawareStrategy</ReplicaPlacementStrategy>
      <ReplicationFactor>3</ReplicationFactor>
      <EndPointSnitch>org.apache.cassandra.locator.EndPointSnitch</EndPointSnitch>
    </Keyspace>

  </Keyspaces>

  <Authenticator>org.apache.cassandra.auth.AllowAllAuthenticator</Authenticator>

  <Partitioner>org.apache.cassandra.dht.RandomPartitioner</Partitioner>

  <InitialToken></InitialToken>

  <CommitLogDirectory>/cassandra/commitlog</CommitLogDirectory>
  <DataFileDirectories>
      <DataFileDirectory>/cassandra/data</DataFileDirectory>
  </DataFileDirectories>

  <Seeds>
      <Seed>pmc01</Seed>
      <Seed>pmc02</Seed>
      <Seed>pmc03</Seed>
      <Seed>pmc06</Seed>
      <Seed>pmc07</Seed>
      <Seed>pmc08</Seed>
  </Seeds>

  <!-- Miscellaneous -->

  <!-- Time to wait for a reply from other nodes before failing the command -->
  <RpcTimeoutInMillis>30000</RpcTimeoutInMillis>
  <!-- phi value that must be reached before a host is marked as down.
       most users should never adjust this -->
  <PhiConvictThreshold>10</PhiConvictThreshold>
  <!-- Size to allow commitlog to grow to before creating a new segment -->
  <CommitLogRotationThresholdInMB>128</CommitLogRotationThresholdInMB>

  <!-- Local hosts and ports -->

  <ListenAddress></ListenAddress>
  <!-- internal communications port -->
  <StoragePort>7000</StoragePort>

  <ThriftAddress></ThriftAddress>
  <!-- Thrift RPC port (the port clients connect to). -->
  <ThriftPort>9160</ThriftPort>

  <ThriftFramedTransport>false</ThriftFramedTransport>


  <!--======================================================================-->
  <!-- Memory, Disk, and Performance                                        -->
  <!--======================================================================-->

  <!--
   ~ Access mode.  mmapped i/o is substantially faster, but only practical on
   ~ a 64bit machine (which notably does not include EC2 "small" instances)
   ~ or relatively small datasets.  "auto", the safe choice, will enable
   ~ mmapping on a 64bit JVM.  Other values are "mmap", "mmap_index_only"
   ~ (which may allow you to get part of the benefits of mmap on a 32bit
   ~ machine by mmapping only index files) and "standard".
   ~ (The buffer size settings that follow only apply to standard,
   ~ non-mmapped i/o.)
   -->
  <DiskAccessMode>mmap_index_only</DiskAccessMode>

  <!--
   ~ Size of compacted row above which to log a warning.  (If compacted
   ~ rows do not fit in memory, Cassandra will crash.  This is explained
   ~ in http://wiki.apache.org/cassandra/CassandraLimitations and is
   ~ scheduled to be fixed in 0.7.)
  -->
  <RowWarningThresholdInMB>512</RowWarningThresholdInMB>

  <!--
   ~ Buffer size to use when performing contiguous column slices. Increase
   ~ this to the size of the column slices you typically perform. 
   ~ (Name-based queries are performed with a buffer size of 
   ~ ColumnIndexSizeInKB.)
  -->
  <SlicedBufferSizeInKB>64</SlicedBufferSizeInKB>

  <!--
   ~ Buffer size to use when flushing memtables to disk. (Only one 
   ~ memtable is ever flushed at a time.) Increase (decrease) the index
   ~ buffer size relative to the data buffer if you have few (many) 
   ~ columns per key.  Bigger is only better _if_ your memtables get large
   ~ enough to use the space. (Check in your data directory after your
   ~ app has been running long enough.) -->
  <FlushDataBufferSizeInMB>32</FlushDataBufferSizeInMB>
  <FlushIndexBufferSizeInMB>8</FlushIndexBufferSizeInMB>

  <!--
   ~ Add column indexes to a row after its contents reach this size.
   ~ Increase if your column values are large, or if you have a very large
   ~ number of columns.  The competing causes are, Cassandra has to
   ~ deserialize this much of the row to read a single column, so you want
   ~ it to be small - at least if you do many partial-row reads - but all
   ~ the index data is read for each access, so you don't want to generate
   ~ that wastefully either.
  -->
  <ColumnIndexSizeInKB>64</ColumnIndexSizeInKB>

  <!--
   ~ Flush memtable after this much data has been inserted, including
   ~ overwritten data.  There is one memtable per column family, and 
   ~ this threshold is based solely on the amount of data stored, not
   ~ actual heap memory usage (there is some overhead in indexing the
   ~ columns).
  -->
  <MemtableThroughputInMB>64</MemtableThroughputInMB>
  <!--
   ~ Throughput setting for Binary Memtables.  Typically these are
   ~ used for bulk load so you want them to be larger.
  -->
  <BinaryMemtableThroughputInMB>256</BinaryMemtableThroughputInMB>
  <!--
   ~ The maximum number of columns in millions to store in memory per
   ~ ColumnFamily before flushing to disk.  This is also a per-memtable
   ~ setting.  Use with MemtableThroughputInMB to tune memory usage.
  -->
  <MemtableOperationsInMillions>0.3</MemtableOperationsInMillions>
  <!--
   ~ The maximum time to leave a dirty memtable unflushed.
   ~ (While any affected columnfamilies have unflushed data from a
   ~ commit log segment, that segment cannot be deleted.)
   ~ This needs to be large enough that it won't cause a flush storm
   ~ of all your memtables flushing at once because none has hit
   ~ the size or count thresholds yet.  For production, a larger
   ~ value such as 1440 is recommended.
  -->
  <MemtableFlushAfterMinutes>60</MemtableFlushAfterMinutes>

  <!--
   ~ Unlike most systems, in Cassandra writes are faster than reads, so
   ~ you can afford more of those in parallel.  A good rule of thumb is 2
   ~ concurrent reads per processor core.  Increase ConcurrentWrites to
   ~ the number of clients writing at once if you enable CommitLogSync +
   ~ CommitLogSyncDelay. -->
  <ConcurrentReads>8</ConcurrentReads>
  <ConcurrentWrites>32</ConcurrentWrites>

  <!--
   ~ CommitLogSync may be either "periodic" or "batch."  When in batch
   ~ mode, Cassandra won't ack writes until the commit log has been
   ~ fsynced to disk.  It will wait up to CommitLogSyncBatchWindowInMS
   ~ milliseconds for other writes, before performing the sync.

   ~ This is less necessary in Cassandra than in traditional databases
   ~ since replication reduces the odds of losing data from a failure
   ~ after writing the log entry but before it actually reaches the disk.
   ~ So the other option is "periodic," where writes may be acked immediately
   ~ and the CommitLog is simply synced every CommitLogSyncPeriodInMS
   ~ milliseconds.
  -->
  <CommitLogSync>periodic</CommitLogSync>
  <!--
   ~ Interval at which to perform syncs of the CommitLog in periodic mode.
   ~ Usually the default of 10000ms is fine; increase it if your i/o
   ~ load is such that syncs are taking excessively long times.
  -->
  <CommitLogSyncPeriodInMS>10000</CommitLogSyncPeriodInMS>
  <!--
   ~ Delay (in milliseconds) during which additional commit log entries
   ~ may be written before fsync in batch mode.  This will increase
   ~ latency slightly, but can vastly improve throughput where there are
   ~ many writers.  Set to zero to disable (each entry will be synced
   ~ individually).  Reasonable values range from a minimal 0.1 to 10 or
   ~ even more if throughput matters more than latency.
  -->
  <!-- <CommitLogSyncBatchWindowInMS>1</CommitLogSyncBatchWindowInMS> --> 

  <!--
   ~ Time to wait before garbage-collection deletion markers.  Set this to
   ~ a large enough value that you are confident that the deletion marker
   ~ will be propagated to all replicas by the time this many seconds has
   ~ elapsed, even in the face of hardware failures.  The default value is
   ~ ten days.
  -->
  <GCGraceSeconds>864000</GCGraceSeconds>
</Storage>