Integral Accounting Enterprise Help System

<body leftmargin="0" topmargin="0" rightmargin="0" bottommargin="0" marginwidth="0" marginheight="0" class="body_workspace"> <html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns="http://www.w3.org/TR/REC-html40"> <head> <font face="Tahoma" size="1" color="#2D4B79"> <meta http-equiv=Content-Type content="text/html; charset=windows-1252"> <meta name=ProgId content=Word.Document> <meta name=Generator content="Microsoft Word 11"> <meta name=Originator content="Microsoft Word 11"> <link rel=File-List href="SSIClustersHomepage_files/filelist.xml"> <title>SSI Clusters</title> </font>  <style>  </style>  </head> </font> <body lang=EN-US link=navy vlink=purple> <div class=Section1> <p class=MsoNormal style='text-align:justify'><b> <span style='font-family:Tahoma'><font color="#2D4B79" size="4">SSI</font><font color="#2D4B79" size="4"> Clusters</font><o:p></o:p></span></b></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">The main <span class=GramE>disadvantages of clusters based on grid computing methods (MPL – Message Parsing Layers etc.) is</span> that application development and porting becomes very difficult and costly. This is <span class=GramE>specially</span> true for financial applications were application costs are more than hardware.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">To solve this problem, the next generation clusters have evolved (or evolving) which are called <b style='mso-bidi-font-weight:normal'>SSI</b> – <b style='mso-bidi-font-weight:normal'><u>S</u></b>ingle <b style='mso-bidi-font-weight: normal'><u>S</u></b>ystem <b style='mso-bidi-font-weight:normal'><u>I</u></b>mage clusters. It is a form of distributed computing in which by using a common interface multiple networks, distributed databases or servers appear to the user as one system. In other words, the operating system environment is shared by all nodes in the system.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Which means, all the node see same operating system environment with added up resources. And ideally this means -</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify;text-indent:-.25in; mso-list:l0 level1 lfo1;tab-stops:.5in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'> <font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'>l</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'><font size="1">        </font> </span></span><![endif]></font><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Single port entry</font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify;text-indent:-.25in; mso-list:l0 level1 lfo1;tab-stops:.5in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'> <font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'>l</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'><font size="1">        </font> </span></span><![endif]></font><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Single file namespace</font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify;text-indent:-.25in; mso-list:l0 level1 lfo1;tab-stops:.5in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'> <font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'>l</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'><font size="1">        </font> </span></span><![endif]></font><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Single i/o space </font> <o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify;text-indent:-.25in; mso-list:l0 level1 lfo1;tab-stops:.5in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'> <font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'>l</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'><font size="1">        </font> </span></span><![endif]></font><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Single point of management control</font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify;text-indent:-.25in; mso-list:l0 level1 lfo1;tab-stops:.5in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'> <font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'>l</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'><font size="1">        </font> </span></span><![endif]></font><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Single virtual network</font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify;text-indent:-.25in; mso-list:l0 level1 lfo1;tab-stops:.5in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'> <font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'>l</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'><font size="1">        </font> </span></span><![endif]></font><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Single Memory space</font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify;text-indent:-.25in; mso-list:l0 level1 lfo1;tab-stops:.5in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'> <font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'>l</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'><font size="1">        </font> </span></span><![endif]></font><span style='font-family:Tahoma'> <font color="#2D4B79"><font size="1">Single process space and single </font> <span class=GramE><font size="1">init !!</font></span></font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify;text-indent:-.25in; mso-list:l0 level1 lfo1;tab-stops:.5in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'> <font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'>l</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Wingdings; mso-bidi-font-family:Wingdings'><font size="1">        </font> </span></span><![endif]></font><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Single /proc </font> <o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">This means your application needs no modifications, the operating system takes care of migrating application threads between nodes.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">All long as the application is threaded and can use threads <span class=GramE>effectively,</span> it will work without modification on an SSI cluster.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">There are a very few open source projects which are able to achieve this properly.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Distributions/Projects </font> <o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <ol style='margin-top:0in' start=1 type=1> <li class=MsoNormal style='text-align:justify;mso-list:l1 level1 lfo2; tab-stops:.5in'><font color="#2D4B79"><span class=SpellE><b style='mso-bidi-font-weight:normal'> <span style='font-family:Tahoma'><font size="1">OpenMosix</font></span></b></span></font><span style='font-family:Tahoma'><font size="1" color="#2D4B79"> – This still uses 2.4 kernel <span class=GramE>( based</span> on FC2). </font> <o:p></o:p></span></li> </ol> <p class=MsoNormal style='margin-left:.5in;text-align:justify'> <span style='font-family:Tahoma'><font size="1" color="#2D4B79">It manages to create SSI <span class=GramE>to<span style='mso-spacerun:yes'> </span>quite</span> an extent but fails to recover when a node faults. The upcoming 2.6 kernel release would likely take care of these things.</font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify'> <span style='font-family:Tahoma'><o:p><font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify'><span class=GramE><span style='font-family:Tahoma'><font size="1" color="#2D4B79">It somewhat fails to live up to expectations when 2.6 kernel features like network and storage drivers are required.</font></span></span><span style='font-size:10.0pt;font-family: Arial'><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify'> <span style='font-family:Tahoma'><o:p><font size="1" color="#2D4B79"> </font></o:p></span></p> <ol style='margin-top:0in' start=2 type=1> <li class=MsoNormal style='text-align:justify;mso-list:l1 level1 lfo2; tab-stops:.5in'><font color="#2D4B79"><span class=SpellE><b style='mso-bidi-font-weight:normal'> <span style='font-family:Tahoma'><font size="1">OpenSSI</font></span></b></span></font><span style='font-family:Tahoma'><font size="1" color="#2D4B79"> – Much recent but mature than <span class=SpellE>OpenMosix</span>. </font> <o:p></o:p></span></li> </ol> <p class=MsoNormal style='margin-left:.5in;text-align:justify'> <span style='font-family:Tahoma'><font size="1" color="#2D4B79">It meets almost all the SSI standards and is fault tolerant to quite an extent.</font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify'> <span style='font-family:Tahoma'><o:p><font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify'> <span style='font-family:Tahoma'><font color="#2D4B79"><font size="1">OpenSSI-1.9 (2.0 beta) comes with all the 2.6 kernel features and network drivers. </font> <span class=GramE> <font size="1">It also <span class=SpellE>suppports</span> PVFS and GFS to create a single device namespace.</font></span></font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify'> <span style='font-family:Tahoma'><o:p><font size="1" color="#2D4B79"> </font></o:p></span></p> <ol style='margin-top:0in' start=3 type=1> <li class=MsoNormal style='text-align:justify;mso-list:l1 level1 lfo2; tab-stops:.5in'><font color="#2D4B79"><span class=SpellE><b style='mso-bidi-font-weight:normal'> <span style='font-family:Tahoma'><font size="1">ClusterKnoppix</font></span></b></span></font><span style='font-family:Tahoma'><font size="1"><font color="#2D4B79"> (</font><a href="http://clusterknoppix.sw.be/"><font color="#2D4B79">http://clusterknoppix.sw.be/</font></a><font color="#2D4B79">)</font></font><o:p></o:p></span></li> </ol> <p class=MsoNormal style='margin-left:.5in;text-align:justify'> <span style='font-family:Tahoma'><font size="1" color="#2D4B79">This is ready to use <span class=SpellE>OpenMosix</span> bases distribution which can help you setup a small cluster in a very short time. This can be used </font> <o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><font color="#2D4B79"><span class=SpellE> <span style='font-family:Tahoma'><font size="1">OpenSSI</font></span></span></font><span style='font-family:Tahoma'><font size="1" color="#2D4B79"> and <span class=SpellE>OpenMosix</span> are just projects which provide a couple of <span class=SpellE>RPMs</span> which include a patched up kernel and some basic cluster monitoring software.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><font color="#2D4B79"><span class=SpellE> <span style='font-family:Tahoma'><font size="1">OpenSSI</font></span></span></font><span style='font-family:Tahoma'><font size="1" color="#2D4B79"> takes advantage of two more projects – Open <span class=SpellE>Cluste</span> <span class=SpellE>Intrastructure</span> (<span class=SpellE>OpenCI</span>) and Linux Virtual Server (LVS) to manage cluster and make it more fault <span class=SpellE>tollerent</span>.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><b> <span style='font-family:Tahoma'><font size="1" color="#2D4B79">Technical information on SSI</font><o:p></o:p></span></b></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">The SSI model uses different techniques to create a single image. After <span class=SpellE>linux</span> kernel 2.6 many of these projects got a big boost from some new features in introduced in the kernel. </font> <o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Here is a brief over view -</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><u> <span style='font-family:Tahoma'><font size="1" color="#2D4B79">Network</font><o:p></o:p></span></u></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Almost all the projects use LVS (Linux Virtual Server) or like functionality which is build into 2.6 <span class=GramE>kernel</span>. The load-balancing the network connections by making all the nodes listen of a particular IP on its “lo” (loop back) network interface. Which means they would never reply to any <span class=SpellE><span class=GramE>arp</span></span> requests for that IP, but would server any incoming connections.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Then only master service the <span class=SpellE><span class=GramE>arp</span></span> requests and pass the connection to different server depending upon the load.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><u> <span style='font-family:Tahoma'><font size="1" color="#2D4B79">Process</font><o:p></o:p></span></u></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">If the migrating process/thread has some open file-descriptors or shared inter-process memory in use, the parent (one who starts migration) starts of a ghost process locally which keeps track of what ever resources the threads needs on the original/parent node.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">This technique also helps in fault-tolerance.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><u> <span style='font-family:Tahoma'><font size="1" color="#2D4B79">Device and File-system </font> <o:p></o:p></span></u></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">The uniformity of file-system and storage device is handled by PVFS or GFS. Both of them have something called <span class=GramE>i/o</span> fencing and global lock managers which help the nodes synchronize the locking and concurrency issues which writing to the disk.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><u> <span style='font-family:Tahoma'><font size="1" color="#2D4B79">Other Changes </font> <o:p></o:p></span></u></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">The proc and process management hooks have <span class=SpellE>beed</span> added. A detailed description of this can be obtained from the site <span class=GramE>( and</span> is beyond the scope of this documents).</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><font color="#2D4B79"><span class=SpellE><b> <span style='font-family:Tahoma'><font size="1">OpenSSI</font></span></b></span></font><b><span style='font-family:Tahoma'><font color="#2D4B79"><font size="1"> Vs </font> <span class=SpellE> <font size="1">OpenMosix</font></span></font><o:p></o:p></span></b></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">I am very sure you must be wondering now <span class=SpellE>whats</span> the difference between <span class=SpellE>OpenSSi</span> and <span class=SpellE><span class=GramE>OpenMosix</span></span><span class=GramE> ..</span> <span class=GramE>here</span> is a bit old but still very much valid summary -</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><a href="http://sourceforge.net/mailarchive/forum.php?thread_id=5860473&forum_id=21441"> <font size="1" color="#2D4B79">http://sourceforge.net/mailarchive/forum.php?thread_id=5860473&forum_id=21441</font></a><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">But, after you Read this also read the refute by <span class=SpellE>OpenMosix</span> guys -</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><a href="http://openmosix.sourceforge.net/openssi_refute.html"> <font size="1" color="#2D4B79">http://openmosix.sourceforge.net/openssi_refute.html</font></a><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span class=GramE> <span style='font-family:Tahoma'><font size="1" color="#2D4B79">Although, the later link is not very much correct.</font></span></span><span style='font-size:10.0pt;font-family:Arial'><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><b> <span style='font-family:Tahoma'><font size="1" color="#2D4B79">Building SSI cluster </font> <o:p></o:p></span></b></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">The hardware <span class=GramE>requirements,</span> interconnect and clustering basics of a SSI cluster are no different from the master/slave clusters. </font> <o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">The installation also is much <span class=GramE>simpler,</span> SSI doesn't require you to install the OS on all the nodes but just the master node. But, the compute nodes must be network bootable <span class=SpellE>i.e</span> support PXE or Ethernet <span class=GramE>boot<span style='mso-spacerun:yes'> </span>options</span>.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><font color="#2D4B79"><span class=SpellE> <span style='font-family:Tahoma'><font size="1">OpenMosix</font></span></span></font><span style='font-family:Tahoma'><font size="1" color="#2D4B79"> and <span class=SpellE>OpenSSI</span> have slightly different installation procedures, but to give an overview the following steps are involved -</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <ol style='margin-top:0in' start=1 type=1> <li class=MsoNormal style='text-align:justify;mso-list:l2 level1 lfo3; tab-stops:.5in'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Install FC3/FC2 (depending upon the distribution) on master node</font><o:p></o:p></span></li> <li class=MsoNormal style='text-align:justify;mso-list:l2 level1 lfo3; tab-stops:.5in'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Decide the network topology (as discussed previously)</font><o:p></o:p></span></li> <li class=MsoNormal style='text-align:justify;mso-list:l2 level1 lfo3; tab-stops:.5in'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Install distribution RPMS ( this has modified kernel and a few apps)</font><o:p></o:p></span></li> <li class=MsoNormal style='text-align:justify;mso-list:l2 level1 lfo3; tab-stops:.5in'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Run a configuration script which -</font><o:p></o:p></span></li> </ol> <p class=MsoNormal style='margin-left:.75in;text-align:justify;text-indent: -.25in;mso-list:l2 level2 lfo3;tab-stops:.75in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'><font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Arial'>1.</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Arial'><font size="1">       </font> </span></span><![endif]></font><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Configures the boot loader to boot from a local partition</font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.75in;text-align:justify;text-indent: -.25in;mso-list:l2 level2 lfo3;tab-stops:.75in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'><font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Arial'>2.</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Arial'><font size="1">       </font> </span></span><![endif]></font><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Takes <span class=SpellE>mac</span> addresses of nodes and prepares boot image for them</font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.75in;text-align:justify;text-indent: -.25in;mso-list:l2 level2 lfo3;tab-stops:.75in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'><font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Arial'>3.</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Arial'><font size="1">       </font> </span></span><![endif]></font><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Sets up PVFS or GFS</font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.75in;text-align:justify;text-indent: -.25in;mso-list:l2 level2 lfo3;tab-stops:.75in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'><font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Arial'>4.</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Arial'><font size="1">       </font> </span></span><![endif]></font><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Kicks of some clustering software configuration (for LVS and <span class=SpellE>OpenCI</span>)</font><o:p></o:p></span></p> <ol style='margin-top:0in' start=5 type=1> <li class=MsoNormal style='text-align:justify;mso-list:l2 level1 lfo3; tab-stops:.5in'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Reboot</font><o:p></o:p></span></li> </ol> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><font color="#2D4B79"><span class=GramE> <span style='font-family:Tahoma'><font size="1">and</font></span></span></font><span style='font-family:Tahoma'><font size="1" color="#2D4B79"> you are ready with a cluster. <span class=SpellE>ClusterKnoppix</span> comes with some pre-configured <span class=GramE>software<span style='mso-spacerun:yes'> </span>and</span> comes very handy if you want to test SSI out. </font> <o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font color="#2D4B79"><font size="1">And this may take you by surprise but with <span class=SpellE>OpenSSI</span> you can use <span class=SpellE>Xwindows</span> applications also ... that too from my </font> <span class=GramE><font size="1">node !!</font></span></font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><b><u> <span style='font-family:Tahoma'><font size="1" color="#2D4B79">Disadvantages of SSI</font><o:p></o:p></span></u></b></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">The only applications which can take full advantages for <span class=SpellE>openSSI</span> are threaded applications like the <span class=SpellE>webserver</span>. Threads and processes can be migrated to other nodes but there is a cost of performance associated with it.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Also, due to these restrictions adding one more <span class=GramE>node</span> doesn't linearly add to performance of the application or the cluster.</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Where <span class=GramE>You</span> can't use clustering -</font><o:p></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <ol style='margin-top:0in' start=1 type=1> <li class=MsoNormal style='text-align:justify;mso-list:l3 level1 lfo4; tab-stops:.5in'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">High-end Database like Oracle.<span style='mso-spacerun:yes'> </span>Because of two reasons –</font><o:p></o:p></span></li> </ol> <p class=MsoNormal style='margin-left:.75in;text-align:justify;text-indent: -.25in;mso-list:l3 level2 lfo4;tab-stops:.75in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'><font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Arial'>1.</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Arial'><font size="1">       </font> </span></span><![endif]><span class=GramE><span style='font-family:Tahoma'> <font size="1">they</font></span></span></font><span style='font-family: Tahoma'><font size="1" color="#2D4B79"> manage there threads on there own, for concurrency. </font> <o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.75in;text-align:justify;text-indent: -.25in;mso-list:l3 level2 lfo4;tab-stops:.75in'><font color="#2D4B79"><![if !supportLists]><span style='mso-list:Ignore'><font face="Tahoma" size="1"> <span style='mso-fareast-font-family:Arial'>2.</span></font><span style='font-style:normal; font-variant:normal; font-weight:normal; font-family:Tahoma; mso-fareast-font-family:Arial'><font size="1">       </font> </span></span><![endif]></font><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">They use direct disk I/O and bypass the file-system</font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.75in;text-align:justify'> <span style='font-family:Tahoma'><o:p><font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify'> <span style='font-family:Tahoma'><font size="1" color="#2D4B79">Some distributed <span class=GramE>database are</span> specially designed to work with the cluster.</font><o:p></o:p></span></p> <p class=MsoNormal style='margin-left:.5in;text-align:justify'> <span style='font-family:Tahoma'><o:p><font size="1" color="#2D4B79"> </font></o:p></span></p> <ol style='margin-top:0in' start=2 type=1> <li class=MsoNormal style='text-align:justify;mso-list:l3 level1 lfo4; tab-stops:.5in'><span style='font-family:Tahoma'> <font size="1" color="#2D4B79">Heavy I/O based <span class=GramE>applications ..</span> <span class=GramE>clustering</span> file-systems specially PVFS is known to be less reliable and available compared to other normal file-systems. Also they lag in performance. </font> <o:p></o:p></span></li> </ol> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal style='text-align:justify'><span style='font-family:Tahoma'><o:p> <font size="1" color="#2D4B79"> </font></o:p></span></p> <p class=MsoNormal><font color="#2D4B79"><span style='font-family:Tahoma'><o:p> <font size="1"> </font></o:p></span></p> </div> </body>