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    <title>Durable Memory - Apache Ignite</title>
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        <section id="durable-memory" class="page-section">
            <h1 class="first">Durable Memory</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-7 col-xs-12" style="padding-left:0; padding-right:0;">
                    <p>
                        Apache Ignite is based on the <nobr>Durable Memory</nobr>
                        architecture that allows storing and processing data and indexes both in memory and on disk
                        when the <a href="/arch/persistence.html">Ignite Native Persistence</a> feature is enabled.
                    </p>
                    <p>
                        The durable memory architecture helps achieve the performance and scale of in-memory computing
                        together with the disk durability and strong consistency in one system.
                    </p>
                </div>

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            <p>
                Ignite's Durable Memory operates in a way similar to the Virtual Memory of operating systems
                such as Linux. However, one significant difference between these two is that the Durable Memory,
                in addition to keeping the whole or partial data set in memory, always keeps the whole data set with
                indexes on disk (assuming that Ignite Native Persistence is enabled), while Virtual Memory uses the
                disk when it runs out of RAM, for swapping purposes only.
            </p>

            <p>
                Following are the advantages and characteristics of Apache Ignite as a platform when Durable Memory
                and Ignite Native Persistence are used together:
            </p>
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                <div class="page-heading">In-Memory</div>
                <ul class="page-list">
                    <li>Off-Heap memory</li>
                    <li>Removes noticeable GC pauses</li>
                    <li>Automatic Defragmentation</li>
                    <li>Predictable memory consumption</li>
                    <li>Boosts SQL performance</li>
                </ul>
            </div>
            <div class="col-sm-6 col-md-6 col-xs-12" style="padding-left:0; padding-right:0;">
                <div class="page-heading">On Disk</div>
                <ul class="page-list">
                    <li>Optional Persistence</li>
                    <li>Support of flash, SSD, Intel 3D Xpoint</li>
                    <li>Stores superset of data</li>
                    <li>Fully Transactional</li>
                    <ul>
                        <li>Write-Ahead-Log (WAL)</li>
                    </ul>
                    <li>Instantaneous Cluster Restarts</li>
                </ul>
            </div>
            <p>Read more on the <a href="https://apacheignite.readme.io/docs/durable-memory" target="_blank">main documentation page</a>.</p>
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