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ChangeSet
1.2637 05/03/05 11:43:56 jon@stripped +1 -0
Cluster FAQ:
- Added "What is an arbitrator?" (many thanks to
Stewart and Mikael)
- Added note about when to expect win32 support
for Cluster
Docs/manual.texi
1.2456 05/03/05 11:43:51 jon@stripped +44 -15
Cluster FAQ:
- Added "What is an arbitrator?" (many thanks to
Stewart and Mikael)
- Added note about when to expect win32 support
for Cluster
# This is a BitKeeper patch. What follows are the unified diffs for the
# set of deltas contained in the patch. The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User: jon
# Host: gigan.site
# Root: /home/jon/bk/mysqldoc
--- 1.2455/Docs/manual.texi 2005-03-05 06:08:51 +10:00
+++ 1.2456/Docs/manual.texi 2005-03-05 11:43:51 +10:00
@@ -6563,16 +6563,16 @@
@xref{Windows create option file}.
-@example
+@example
Error: Cannot create Windows service for MySql. Error: 0
@end example
-This error is encountered when you re-install or upgrade MySQL without first stopping
-and removing the existing MySQL service and install MySQL using the
-MySQL Configuration Wizard. This happens because when the Configuration Wizard tries to
+This error is encountered when you re-install or upgrade MySQL without first stopping
+and removing the existing MySQL service and install MySQL using the
+MySQL Configuration Wizard. This happens because when the Configuration Wizard tries to
install the service it finds an existing service with the same name.
-One solution to this problem is to choose a service name other than @code{mysql} when
+One solution to this problem is to choose a service name other than @code{mysql} when
using the configuration wizard. This will allow the new service to be installed correctly,
but leaves the outdated service in place. While this is harmless it is best to remove old
services that are no longer in use.
@@ -63436,8 +63436,8 @@
This support takes advantage of the efficient client/server binary protocol,
provided that you use an appropriate client programming interface. Candidate
interfaces include the MySQL C API client library (for C programs),
-MySQL Connector/J (for Java programs), and MySQL Connector/NET.
-For example, the C API provides a set of function calls that make up its
+MySQL Connector/J (for Java programs), and MySQL Connector/NET.
+For example, the C API provides a set of function calls that make up its
prepared statement API. @xref{C API Prepared statements}.
Other language interfaces can provide support for prepared statements that
use the binary protocol by linking in the C client library. (The mysqli
@@ -74821,10 +74821,10 @@
@item
@emph{With which operating systems can I use Cluster?}
-As of MySQL 4.1.9, MySQL Cluster is officially supported on Linux, Mac OS X, and
-Solaris. We are working to add Cluster support for other platforms, including
-Windows, and our goal is eventually to offer Cluster on all platforms for which
-MySQL itself is supported.
+As of MySQL 4.1.10, MySQL Cluster is officially supported on Linux, Mac OS X,
+and Solaris. We are working to add Cluster support for other platforms,
+including Windows (expected in MySQL Cluster 5.0), and our goal is eventually to
+offer Cluster on all platforms for which MySQL itself is supported.
It may be possible to run Cluster processes on other operating systems
(including Windows), but Cluster on any but the three mentioned here should be
@@ -75081,11 +75081,40 @@
drivers. See @ref{MySQL Cluster Interconnects} for more about using SCI as a
transport mechanism in MySQL Cluster.
-@c Refs: SMH, SCI
+@item
+@emph{What is an arbitrator?}
-@ c *** TODO: Need to answer this question ***
-@c @item
-@c @emph{What is an arbitrator?}
+If one or more nodes in a cluster fail, it is possible that not all cluster
+nodes will not be able to "see" one another. In fact, it is possible that two
+sets of nodes might become isolated from one another in a network partitioning,
+also known as a "split brain" scenario. This type of situation is undesirable
+because each set of nodes tries to behave as though it is the entire cluster.
+
+When cluster nodes go down, there are two possibilities. If more than 50% of the
+remaining nodes can communicate with each other, then we have what is sometimes
+called a "majority rules" situation, and this set of nodes is considered to be
+the cluster. The arbitrator comes into play when there is an even number of
+nodes: in such a case, the set of nodes to which the arbitrator belongs is
+considered to be the cluster, and nodes not belonging to this set are shut down.
+
+The above is somewhat simplified; a more complete explanation taking into
+account node groups follows below:
+
+When all nodes in at least one node group are alive, network partitioning is not
+an issue, because no one portion of the cluster can form a functional cluster.
+The real problem arises when no single node group has all its nodes alive, in
+which case network partitioning (the "split-brain" scenario) becomes possible.
+Then an arbitrator is required. All cluster nodes recognise the same node as the
+arbitrator, which is normally the management server; however, it is possible to
+configure any of the MySQL Servers in the cluster to act as the arbirtrator
+instead. The arbitrator accepts the first set of cluster nodes to contact it,
+and tells the remaining set to die. Arbitrator selection is controlled by the
+@code{ArbitrationRank} configuration parameter for MySQL Server and management
+server nodes. (See @ref{MySQL Cluster MGM Definition} for details.) It should
+also be noted that the role of arbitrator does not in and of itself impose any
+heavy demands upon the host so designated, and thus the artitrator host does not
+need to be particularly fast or to have extra memory especially for this
+purpose.
@item
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| • bk commit - mysqldoc tree (jon:1.2637) | jon | 5 Mar |
