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From: Apache Wiki <wikidiffs@apache.org>
To: Apache Wiki <wikidiffs@apache.org>
Date: Thu, 19 Nov 2009 16:34:47 -0000
Message-ID: <20091119163447.19673.27485@eos.apache.org>
Subject: 
 =?utf-8?q?=5BCassandra_Wiki=5D_Update_of_=22CassandraHardware=22_by_Jonat?=
 =?utf-8?q?hanEllis?=

Dear Wiki user,

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

The "CassandraHardware" page has been changed by JonathanEllis.
http://wiki.apache.org/cassandra/CassandraHardware?action=3Ddiff&rev1=3D2&r=
ev2=3D3

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

  =3D=3D=3D Memory =3D=3D=3D
- The most recently written data resides in memory tables (aka [[MemtableTh=
resholds|memtables]]), but older data that has been flushed to disk can be =
kept in the OS's file-system cache. In other words, ''the more memory, the =
better'', with 1GB being the minimum recommended.
+ The most recently written data resides in memory tables (aka [[MemtableTh=
resholds|memtables]]), but older data that has been flushed to disk can be =
kept in the OS's file-system cache. In other words, ''the more memory, the =
better'', with 1GB being the minimum recommended in a virtualized environme=
nt.  With dedicated hardware there is no reason to use less than 4GB, and a=
t the high end, you see clusters with 16 or 32 GB.
  =

  =3D=3D=3D CPU =3D=3D=3D
  Many workloads will actually be CPU-bound in Cassandra before being memor=
y-bound.  Cassandra is highly concurrent and will make good use of however =
many cores you can give it.  For high-end clusters, quad- or 8-core boxes a=
re good.  If you're running on virtualized machines, consider using a provi=
der such as Rackspace Cloud Servers that allows CPU bursting.
- =

  =

  =3D=3D=3D Disk =3D=3D=3D
  The short answer here is, ''at least 2 disks'', one to keep your `CommitL=
ogDirectory` on, the other to use in `DataFileDirectories`. The exact answe=
r though depends a lot on your usage so it's important to understand what i=
s going on here.