cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Apache Wiki <>
Subject [Cassandra Wiki] Update of "StorageConfiguration" by tuxracer69
Date Sat, 14 Nov 2009 14:33:45 GMT
Dear Wiki user,

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

The "StorageConfiguration" page has been changed by tuxracer69.


  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>
+ <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.
@@ -214, +215 @@

  Number of threads to run when flushing memtables to disk.  Set this to the number of disks
you physically have in your machine allocated for {{{DataDirectory * 2}}}.  If you are planning
to use the Binary Memtable, its recommended to increase the max threads to maintain a higher
quality of service while under load when normal memtables are flushing to disk.
- <FlushMinThreads>1</FlushMinThreads> <FlushMaxThreads>1</FlushMaxThreads>
+ <FlushMinThreads>1</FlushMinThreads> 
+ <FlushMaxThreads>1</FlushMaxThreads>
  The threshold size in megabytes the binary memtable must grow to, before it's submitted
for flushing to disk.

View raw message