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Posted to commits@helix.apache.org by ki...@apache.org on 2012/12/11 23:00:19 UTC
git commit: [HELIX-13] fixing image link
Updated Branches:
refs/heads/master 91cc9bb10 -> b0368e08f
[HELIX-13] fixing image link
Project: http://git-wip-us.apache.org/repos/asf/incubator-helix/repo
Commit: http://git-wip-us.apache.org/repos/asf/incubator-helix/commit/b0368e08
Tree: http://git-wip-us.apache.org/repos/asf/incubator-helix/tree/b0368e08
Diff: http://git-wip-us.apache.org/repos/asf/incubator-helix/diff/b0368e08
Branch: refs/heads/master
Commit: b0368e08f8411962be70bca3895b1c0e556fb565
Parents: 91cc9bb
Author: Kishore Gopalakrishna <g....@gmail.com>
Authored: Tue Dec 11 13:59:55 2012 -0800
Committer: Kishore Gopalakrishna <g....@gmail.com>
Committed: Tue Dec 11 13:59:55 2012 -0800
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.../recipes/rsync_replicated_file_store.md | 16 +++++++-------
1 files changed, 8 insertions(+), 8 deletions(-)
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http://git-wip-us.apache.org/repos/asf/incubator-helix/blob/b0368e08/src/site/markdown/recipes/rsync_replicated_file_store.md
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diff --git a/src/site/markdown/recipes/rsync_replicated_file_store.md b/src/site/markdown/recipes/rsync_replicated_file_store.md
index d29c3ec..290d128 100644
--- a/src/site/markdown/recipes/rsync_replicated_file_store.md
+++ b/src/site/markdown/recipes/rsync_replicated_file_store.md
@@ -2,10 +2,10 @@ Near real time rsync replicated file system
===========================================
Quickdemo
-=========
+---------
* This demo starts 3 instances with id's as ```localhost_12001, localhost_12002, localhost_12003```
-* Each instance stores its files under /tmp/<id>/filestore
+* Each instance stores its files under ```/tmp/<id>/filestore```
* ``` localhost_12001 ``` is designated as the master and ``` localhost_12002 and localhost_12003``` are the slaves.
* Files written to master are replicated to the slaves automatically. In this demo, a.txt and b.txt are written to ```/tmp/localhost_12001/filestore``` and it gets replicated to other folders.
* When the master is stopped, ```localhost_12002``` is promoted to master.
@@ -26,7 +26,7 @@ chmod +x *
```
Overview
-========
+--------
There are many applications that require storage for storing large number of relatively small data files. Examples include media stores to store small videos, images, mail attachments etc. Each of these objects is typically kilobytes, often no larger than a few megabytes. An additional distinguishing feature of these usecases is also that files are typically only added or deleted, rarely updated. When there are updates, they are rare and do not have any concurrency requirements.
@@ -55,7 +55,7 @@ Apache Helix is a generic cluster management framework that makes it very easy t
Rsync can be easily used as a replication channel between servers so that each file gets replicated on multiple servers.
Design
-======
+------
High level
@@ -84,14 +84,14 @@ changes from previous master before taking up mastership. The new master will re
with sequence starting from 1. After this the master will begin accepting writes.
-
+
Rsync based solution
-====================
+-------------------
-
+
This application demonstrate a file store that uses rsync as the replication mechanism. One can envision a similar system where instead of using rsync,
@@ -115,7 +115,7 @@ can implement a custom solution to notify the slave of the changes and also prov
- On demand rsync invoker: This is registered as a listener to change log watcher and on every change invokes rsync to sync only the changed file.
-##### Coordination
+#### Coordination
The coordination between nodes is done by Helix. Helix does the partition management and assigns the partition to multiple nodes based on the replication factor. It elects one the nodes as master and designates others as slaves.
It provides notifications to each node in the form of state transitions ( Offline to Slave, Slave to Master). It also provides notification when there is change is cluster state.