Author: dmagda
Date: Tue Mar  6 23:08:03 2018
New Revision: 1826051

URL: http://svn.apache.org/viewvc?rev=1826051&view=rev
Log:
updated persistence

Modified:
    ignite/site/trunk/arch/persistence.html

Modified: ignite/site/trunk/arch/persistence.html
URL: 
http://svn.apache.org/viewvc/ignite/site/trunk/arch/persistence.html?rev=1826051&r1=1826050&r2=1826051&view=diff
==============================================================================
--- ignite/site/trunk/arch/persistence.html (original)
+++ ignite/site/trunk/arch/persistence.html Tue Mar  6 23:08:03 2018
@@ -53,22 +53,22 @@ under the License.
 
     <main id="main" role="main" class="container">
         <section id="native-persistence" class="page-section">
-            <h1 class="first">Ignite Native Persistence</h1>
+            <h1 class="first">Ignite Persistence</h1>
                 <div class="col-sm-12 col-md-12 col-xs-12" 
style="padding-left:0; padding-right:0;">
                     <div class="col-sm-6 col-md-6 col-xs-12" 
style="padding-left:0; padding-right:0;">
                         <p>
-                            As it is covered in <a 
href="/arch/memorycentric.html">memory-centric storage</a>,
-                            Ignite is widely used as a caching layer (aka. 
data grid) above an existing 3rd
-                            party database such as RDBMS, Apache Cassandra or 
MongoDB. This mode is used to
-                            accelerate the underlying database that persists 
the data.
-                            At the same time Ignite comes with its own 
persistence, that is considered as an alternate
-                            and preferable persistence layer for the Ignite 
cluster.
+                            Ignite is widely used as a caching layer above an 
existing 3rd
+                            party database, such as RDBMS, Apache Cassandra or 
MongoDB, to
+                            accelerate them. At the same time, Ignite comes 
with its own persistence that is considered as an alternate
+                            and preferable persistence layer for an Ignite 
cluster.
                         </p>
+                        <h2 style="padding-top: 10px;">Native Persistence</h2>
                         <p>
                             Ignite native persistence is a distributed, ACID, 
and <nobr>SQL-compliant</nobr> disk store
                             that transparently integrates with Ignite's 
durable memory. Ignite persistence is optional
                             and can be turned on and off. When turned off 
Ignite becomes a pure in-memory store.
                         </p>
+
                     </div>
                     <div class="col-sm-6 col-md-6 col-xs-12" 
style="padding-right:0; top: -10px;">
                         <a href="/images/native_persistence.png"><img 
class="img-responsive" src="/images/native_persistence.png" width="450px" 
style="float:right;" alt="Apache Ignite Native Persistence - Distributed SQL 
Database"/></a>
@@ -80,7 +80,6 @@ under the License.
                     100 entries and RAM has the capacity to store only 20, 
then all 100 will be stored on disk
                     and only 20 will be cached in RAM for better performance.
                 </p>
-
                 <p>
                     The native persistence has the following important 
characteristics:
                 </p>
@@ -170,7 +169,32 @@ under the License.
                         </pre>
                     </div>
                 </div>
-            <p><a 
href="https://apacheignite.readme.io/docs/distributed-persistent-store"; 
target="_blank">Read more</a></p>
+
+            <h2 style="padding-top: 10px;">3rd Party Persistence</h2>
+            <p>
+                Ignite can be used as a caching layer (aka. data grid) above 
an existing 3rd party
+                database - RDBMS, NoSQL, or HDFS. This mode is used to 
accelerate the underlying database that persists
+                the data. Ignite stores data in memory, distributed across 
multiple nodes providing fast data access.
+                It reduces the network overhead caused due to frequent data 
movement between an application and the database.
+                However, there are some limitations in comparison to the 
native persistence. For instance, SQL queries
+                will be executed only on the data that is in RAM, thus, 
requiring to preload all the data set from disk
+                to memory beforehand.
+            </p>
+
+            <h2 style="padding-top: 10px;">Swap Space</h2>
+            <p>
+                If you do not want to use Ignite native persistence or 3rd 
party persistence, you can enable swapping,
+                in which case, Ignite in-memory data will be moved to the swap 
space located on disk if you run out of RAM.
+                When swap space is enabled, Ignites stores data in memory 
mapped files (MMF) whose content will be
+                swapped to disk by the OS depending on the current RAM 
consumption. The swap space is mostly used to
+                avoid out of memory errors (OOME) that might happen if RAM 
consumption goes beyond its capacity and
+                you need more time to scale the cluster out to​ redistribute 
the data sets evenly.
+            </p>
+
+            <div class="page-heading">More Information</div>
+            <p><a 
href="https://apacheignite.readme.io/docs/distributed-persistent-store"; 
target="_blank">Native Persistence</a></p>
+            <p><a href="https://apacheignite.readme.io/docs/3rd-party-store"; 
target="_blank">3rd Party Persistence</a></p>
+            <p><a href="https://apacheignite.readme.io/docs/swap-space"; 
target="_blank">Swap Space</a></p>
         </section>
     </main>
 


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