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<h1 class="topictitle1">Scaling In an Elasticsearch Cluster</h1>
<div id="body0000001338349521"><p id="css_01_0153__en-us_topic_0000001338349521_p18220112044212">If a cluster can process current traffic without fully utilizing its resources, you can scale in the cluster to cut costs.</p>
<div class="section" id="css_01_0153__section7949129142818"><h4 class="sectiontitle">Scenario</h4><p id="css_01_0153__p279410179593">CSS supports multiple scale-in methods, as described in <a href="css_01_0151.html#css_01_0151__table13694163818283">Table 1</a>.</p>

<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" id="css_01_0153__table13694163818283" frame="border" border="1" rules="all"><caption><b>Table 1 </b>Scaling in an Elasticsearch cluster</caption><thead align="left"><tr id="css_01_0153__row2695173812285"><th align="left" class="cellrowborder" valign="top" width="25%" id="mcps1.3.2.3.2.4.1.1"><p id="css_01_0153__p0695143852820">Scenario</p>
</th>
<th align="left" class="cellrowborder" valign="top" width="50%" id="mcps1.3.2.3.2.4.1.2"><p id="css_01_0153__p1269553810282">Description</p>
</th>
<th align="left" class="cellrowborder" valign="top" width="25%" id="mcps1.3.2.3.2.4.1.3"><p id="css_01_0153__p869517387280">Details</p>
</th>
</tr>
</thead>
<tbody><tr id="css_01_0153__row1631519310194"><td class="cellrowborder" valign="top" width="25%" headers="mcps1.3.2.3.2.4.1.1 "><p id="css_01_0153__p1431516310197">Reducing nodes randomly</p>
</td>
<td class="cellrowborder" valign="top" width="50%" headers="mcps1.3.2.3.2.4.1.2 "><p id="css_01_0153__p76949163210">Randomly removes some of the nodes of a cluster, so that it is less costly to keep it running.</p>
</td>
<td class="cellrowborder" valign="top" width="25%" headers="mcps1.3.2.3.2.4.1.3 "><p id="css_01_0153__p1231515313199"><a href="#css_01_0153__en-us_topic_0000001338349521_section1177713055318">Reducing Nodes Randomly</a></p>
</td>
</tr>
<tr id="css_01_0153__row992732131920"><td class="cellrowborder" valign="top" width="25%" headers="mcps1.3.2.3.2.4.1.1 "><p id="css_01_0153__p10928122171910">Removing specified nodes</p>
</td>
<td class="cellrowborder" valign="top" width="50%" headers="mcps1.3.2.3.2.4.1.2 "><p id="css_01_0153__p198542118325">Removes specified nodes of a cluster, so that it is less costly to keep it running.</p>
</td>
<td class="cellrowborder" valign="top" width="25%" headers="mcps1.3.2.3.2.4.1.3 "><p id="css_01_0153__p2092882151912"><a href="#css_01_0153__en-us_topic_0000001338468977_section1177713055318">Removing Specified Nodes</a></p>
</td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="section" id="css_01_0153__en-us_topic_0000001338349521_section12477125117522"><h4 class="sectiontitle">Constraints</h4><ul id="css_01_0153__en-us_topic_0000001338349521_ul1549322814277"><li id="css_01_0153__li1061806182011">To reduce the impact on services, you are advised to perform scale-in during off-peak hours.</li><li id="css_01_0153__li6245202713486">During a scale-in, the data on the to-be-removed nodes needs to be migrated to other nodes. The timeout threshold for data migration is five hours. If data migration is not complete within 5 hours, the cluster scale-in fails. If the cluster stores large amounts of data, you are advised to break down the scale-in task into multiple batches, and complete each batch one at a time.</li><li id="css_01_0153__en-us_topic_0000001338349521_li108232692012">Ensure that the disk usage after scale-in is less than 80% and each AZ has at least one node of each type.</li><li id="css_01_0153__en-us_topic_0000001338468977_li1176612232246">In a cross-AZ cluster, the difference between the numbers of the same type nodes in different AZs cannot exceed 1.</li><li id="css_01_0153__en-us_topic_0000001338468977_li16801597451">For a cluster without master nodes, the number of removed data nodes plus cold data nodes in a scale-in must be fewer than half of the original data nodes plus cold data nodes, and the number of remaining data nodes plus cold data nodes after a scale-in must be greater than the maximum number of index replicas.</li><li id="css_01_0153__en-us_topic_0000001338349521_li79004414393">For a cluster with master nodes, the number of removed master nodes in a scale-in must be fewer than half of the original master nodes. After scale-in, there has to be an odd number of master nodes, and there has to be at least three of them.</li><li id="css_01_0153__en-us_topic_0000001338349521_li7493162820274">In each cluster, the number of nodes supported by each node type varies, depending on the types of nodes used in that cluster. For details, see <a href="#css_01_0153__table144451631608">Table 2</a>.
<div class="tablenoborder"><a name="css_01_0153__table144451631608"></a><a name="table144451631608"></a><table cellpadding="4" cellspacing="0" summary="" id="css_01_0153__table144451631608" frame="border" border="1" rules="all"><caption><b>Table 2 </b>Number of nodes of different types allowed in a single cluster</caption><thead align="left"><tr id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_row1976920435387"><th align="left" class="cellrowborder" valign="top" width="50.529999999999994%" id="mcps1.3.3.2.7.2.2.3.1.1"><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p1976954343811">Node Type</p>
</th>
<th align="left" class="cellrowborder" valign="top" width="49.47%" id="mcps1.3.3.2.7.2.2.3.1.2"><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p1276920435389">Node Quantity</p>
</th>
</tr>
</thead>
<tbody><tr id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_row1769164393820"><td class="cellrowborder" valign="top" width="50.529999999999994%" headers="mcps1.3.3.2.7.2.2.3.1.1 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p18769184333816">ess</p>
</td>
<td class="cellrowborder" valign="top" width="49.47%" headers="mcps1.3.3.2.7.2.2.3.1.2 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p127691243123819">ess: 1-32</p>
</td>
</tr>
<tr id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_row177691843183816"><td class="cellrowborder" valign="top" width="50.529999999999994%" headers="mcps1.3.3.2.7.2.2.3.1.1 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p776964317385">ess, ess-master</p>
</td>
<td class="cellrowborder" valign="top" width="49.47%" headers="mcps1.3.3.2.7.2.2.3.1.2 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p9769194317381">ess: 1-200</p>
<p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p1976911438384">ess-master: an odd number ranging from 3 to 9</p>
</td>
</tr>
<tr id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_row107691743183814"><td class="cellrowborder" valign="top" width="50.529999999999994%" headers="mcps1.3.3.2.7.2.2.3.1.1 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p1769443133816">ess, ess-client</p>
</td>
<td class="cellrowborder" valign="top" width="49.47%" headers="mcps1.3.3.2.7.2.2.3.1.2 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p157691943163815">ess: 1-32</p>
<p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p1976917431383">ess-client: 1-32</p>
</td>
</tr>
<tr id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_row57692432388"><td class="cellrowborder" valign="top" width="50.529999999999994%" headers="mcps1.3.3.2.7.2.2.3.1.1 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p18769343203813">ess, ess-cold</p>
</td>
<td class="cellrowborder" valign="top" width="49.47%" headers="mcps1.3.3.2.7.2.2.3.1.2 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p12769194317384">ess: 1-32</p>
<p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p1138220591537">ess-cold: 1-32</p>
</td>
</tr>
<tr id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_row187701743193815"><td class="cellrowborder" valign="top" width="50.529999999999994%" headers="mcps1.3.3.2.7.2.2.3.1.1 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p1477054314389">ess, ess-master, ess-client</p>
</td>
<td class="cellrowborder" valign="top" width="49.47%" headers="mcps1.3.3.2.7.2.2.3.1.2 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p2770164303816">ess: 1-200</p>
<p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p877020432386">ess-master: an odd number ranging from 3 to 9</p>
<p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p177044313389">ess-client: 1-32</p>
</td>
</tr>
<tr id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_row27701443143811"><td class="cellrowborder" valign="top" width="50.529999999999994%" headers="mcps1.3.3.2.7.2.2.3.1.1 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p2770443173816">ess, ess-master, ess-cold</p>
</td>
<td class="cellrowborder" valign="top" width="49.47%" headers="mcps1.3.3.2.7.2.2.3.1.2 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p1777074316382">ess: 1-200</p>
<p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p5770124393818">ess-master: an odd number ranging from 3 to 9</p>
<p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p161801250733">ess-cold: 1-32</p>
</td>
</tr>
<tr id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_row67708433382"><td class="cellrowborder" valign="top" width="50.529999999999994%" headers="mcps1.3.3.2.7.2.2.3.1.1 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p777018438384">ess, ess-client, ess-cold</p>
</td>
<td class="cellrowborder" valign="top" width="49.47%" headers="mcps1.3.3.2.7.2.2.3.1.2 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p077074353816">ess: 1-32</p>
<p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p12770194393813">ess-client: 1-32</p>
<p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p1841425314">ess-cold: 1-32</p>
</td>
</tr>
<tr id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_row7770143153811"><td class="cellrowborder" valign="top" width="50.529999999999994%" headers="mcps1.3.3.2.7.2.2.3.1.1 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p577044333818">ess, ess-master, ess-client, ess-cold</p>
</td>
<td class="cellrowborder" valign="top" width="49.47%" headers="mcps1.3.3.2.7.2.2.3.1.2 "><p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p1777017437384">ess: 1-200</p>
<p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p077034315388">ess-master: an odd number ranging from 3 to 9</p>
<p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p5770144314386">ess-client: 1-32</p>
<p id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_p1278719254314">ess-cold: 1-32</p>
</td>
</tr>
<tr id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_row14267396512"><td class="cellrowborder" colspan="2" valign="top" headers="mcps1.3.3.2.7.2.2.3.1.1 mcps1.3.3.2.7.2.2.3.1.2 "><div class="note" id="css_01_0153__css_01_0151_note3723104323311"><span class="notetitle"> NOTE: </span><div class="notebody"><ul id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_ul12497123683"><li id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_li64981323284"><strong id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_b1543078192814">ess</strong>: data node, which is the default node type that is mandatory for cluster creation. The other three node types are optional.</li><li id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_li6498112311818"><strong id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_b14242174542716">ess-master</strong>: master node</li><li id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_li114982231584"><strong id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_b051753122720">ess-client</strong>: client node</li><li id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_li64984238813"><strong id="css_01_0153__css_01_0151_en-us_topic_0000001285669680_b151201057162715">ess-cold</strong>: cold data node</li></ul>
</div></div>
</td>
</tr>
</tbody>
</table>
</div>
</li></ul>
</div>
<div class="section" id="css_01_0153__en-us_topic_0000001338349521_section11686944145218"><h4 class="sectiontitle">Prerequisites</h4><ul id="css_01_0153__ul7626104515343"><li id="css_01_0153__li8626154513420">The cluster is in the <strong id="css_01_0153__b58981733481821">Available</strong> state and has no ongoing tasks.</li><li id="css_01_0153__li1466414473510">All mission-critical data has been backed up before a cluster scale-in. This is to prevent data loss.</li></ul>
</div>
<div class="section" id="css_01_0153__en-us_topic_0000001338349521_section1177713055318"><a name="css_01_0153__en-us_topic_0000001338349521_section1177713055318"></a><a name="en-us_topic_0000001338349521_section1177713055318"></a><h4 class="sectiontitle">Reducing Nodes Randomly</h4><ol id="css_01_0153__en-us_topic_0000001338349521_ol373518361145"><li id="css_01_0153__en-us_topic_0000001338349521_li1173513611411">Log in to the <span id="css_01_0153__text34776665011162">CSS</span> management console.</li><li id="css_01_0153__li108716541501">In the navigation pane, choose a cluster type. The cluster management page is displayed.</li><li id="css_01_0153__en-us_topic_0000001285669680_li17735636141417">In the cluster list, select the target cluster, and choose <strong id="css_01_0153__b1538386572428">More</strong> &gt; <strong id="css_01_0153__b16102755162428">Modify Configuration</strong> in the <strong id="css_01_0153__b16752154922428">Operation</strong> column. The <strong id="css_01_0153__b223295402428">Modify Configuration</strong> page is displayed.</li><li id="css_01_0153__li993453153514">Click the <strong id="css_01_0153__b10564014402428">Scale Cluster</strong> tab.</li><li id="css_01_0153__en-us_topic_0000001338349521_li13735736141416">Click <strong id="css_01_0153__en-us_topic_0000001338349521_b14556183015120">Scale in</strong> to set parameters.
<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" id="css_01_0153__table83751919104117" frame="border" border="1" rules="all"><caption><b>Table 3 </b>Reducing nodes randomly</caption><thead align="left"><tr id="css_01_0153__row1937541910412"><th align="left" class="cellrowborder" valign="top" width="30%" id="mcps1.3.5.2.5.2.2.3.1.1"><p id="css_01_0153__p837561910415">Parameter</p>
</th>
<th align="left" class="cellrowborder" valign="top" width="70%" id="mcps1.3.5.2.5.2.2.3.1.2"><p id="css_01_0153__p1376161914115">Description</p>
</th>
</tr>
</thead>
<tbody><tr id="css_01_0153__row7376319114110"><td class="cellrowborder" valign="top" width="30%" headers="mcps1.3.5.2.5.2.2.3.1.1 "><p id="css_01_0153__p3376171911410">Action</p>
</td>
<td class="cellrowborder" valign="top" width="70%" headers="mcps1.3.5.2.5.2.2.3.1.2 "><p id="css_01_0153__p3376219164112">Select <strong id="css_01_0153__b15801714822428">Scale in</strong>.</p>
</td>
</tr>
<tr id="css_01_0153__row183761419164111"><td class="cellrowborder" valign="top" width="30%" headers="mcps1.3.5.2.5.2.2.3.1.1 "><p id="css_01_0153__p23769190415">Resources</p>
</td>
<td class="cellrowborder" valign="top" width="70%" headers="mcps1.3.5.2.5.2.2.3.1.2 "><p id="css_01_0153__p13762198416">Shows the change of resources for this scale-in operation.</p>
</td>
</tr>
<tr id="css_01_0153__row537618191419"><td class="cellrowborder" valign="top" width="30%" headers="mcps1.3.5.2.5.2.2.3.1.1 "><p id="css_01_0153__p737610192416">Nodes</p>
</td>
<td class="cellrowborder" valign="top" width="70%" headers="mcps1.3.5.2.5.2.2.3.1.2 "><p id="css_01_0153__p17376161934115">Reduce the number of nodes in the <strong id="css_01_0153__b12954438232428">Nodes</strong> column. You can change multiple node types at the same time.</p>
<p id="css_01_0153__p95451432191513">For the value range of node quantity for each node type, see <a href="#css_01_0153__table144451631608">Table 2</a>.</p>
</td>
</tr>
</tbody>
</table>
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</li><li id="css_01_0153__en-us_topic_0000001338349521_li173623641418">Click <span class="uicontrol" id="css_01_0153__uicontrol34426042311"><b>Next</b></span>.</li><li id="css_01_0153__en-us_topic_0000001338349521_li13737436141418">Confirm the information and click <strong id="css_01_0153__en-us_topic_0000001338349521_b17057534894732">Submit</strong>.</li><li id="css_01_0153__en-us_topic_0000001338349521_li11772194412145">Click <span class="uicontrol" id="css_01_0153__en-us_topic_0000001338349521_uicontrol26178789894732"><b>Back to Cluster List</b></span> to switch to the <strong id="css_01_0153__en-us_topic_0000001338349521_b137271613994732">Clusters</strong> page. The <span class="parmname" id="css_01_0153__en-us_topic_0000001338349521_parmname76355443715"><b>Task Status</b></span> is <span class="parmvalue" id="css_01_0153__en-us_topic_0000001338349521_parmvalue269155419375"><b>Scaling in</b></span>. When <span class="parmname" id="css_01_0153__en-us_topic_0000001338349521_parmname31911726162420"><b>Cluster Status</b></span> changes to <span class="parmvalue" id="css_01_0153__en-us_topic_0000001338349521_parmvalue121972262247"><b>Available</b></span>, the cluster has been successfully scaled in.</li></ol>
</div>
<div class="section" id="css_01_0153__en-us_topic_0000001338468977_section1177713055318"><a name="css_01_0153__en-us_topic_0000001338468977_section1177713055318"></a><a name="en-us_topic_0000001338468977_section1177713055318"></a><h4 class="sectiontitle">Removing Specified Nodes</h4><ol id="css_01_0153__en-us_topic_0000001338468977_ol373518361145"><li id="css_01_0153__en-us_topic_0000001338468977_li1173513611411">Log in to the CSS management console.</li><li id="css_01_0153__li54875151923">In the navigation pane, choose a cluster type. The cluster management page is displayed.</li><li id="css_01_0153__li1348719151623">In the cluster list, select the target cluster, and choose <strong id="css_01_0153__b14945530662428">More</strong> &gt; <strong id="css_01_0153__b4426083922428">Modify Configuration</strong> in the <strong id="css_01_0153__b19796458142428">Operation</strong> column. The <strong id="css_01_0153__b2996057452428">Modify Configuration</strong> page is displayed.</li><li id="css_01_0153__en-us_topic_0000001338468977_li239201117417">On the <strong id="css_01_0153__b1620187802428">Modify Configuration</strong> page, click the <strong id="css_01_0153__b1074551462428">Scale In</strong> tab.</li><li id="css_01_0153__li37631229090">Set scale-in parameters.
<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" id="css_01_0153__table3127124041713" frame="border" border="1" rules="all"><caption><b>Table 4 </b>Removing specified nodes</caption><thead align="left"><tr id="css_01_0153__row1712711404176"><th align="left" class="cellrowborder" valign="top" width="30%" id="mcps1.3.6.2.5.1.2.3.1.1"><p id="css_01_0153__p15127124014172">Parameter</p>
</th>
<th align="left" class="cellrowborder" valign="top" width="70%" id="mcps1.3.6.2.5.1.2.3.1.2"><p id="css_01_0153__p1712704016171">Description</p>
</th>
</tr>
</thead>
<tbody><tr id="css_01_0153__row161270402176"><td class="cellrowborder" valign="top" width="30%" headers="mcps1.3.6.2.5.1.2.3.1.1 "><p id="css_01_0153__p171871929151813">Node Type</p>
</td>
<td class="cellrowborder" valign="top" width="70%" headers="mcps1.3.6.2.5.1.2.3.1.2 "><p id="css_01_0153__p1718622920180">Expand the node type that needs be changed to show all nodes under it. Select the nodes you want to remove.</p>
</td>
</tr>
</tbody>
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</li><li id="css_01_0153__en-us_topic_0000001338468977_li173623641418">Click <span class="uicontrol" id="css_01_0153__uicontrol1688394753"><b>Next</b></span>.</li><li id="css_01_0153__en-us_topic_0000001338468977_li462507104311">Confirm the change information and click <strong id="css_01_0153__b5850887772428">Submit</strong>. In the confirm dialog box, choose to migrate data, which helps to prevent data loss, and click <strong id="css_01_0153__b19707470832428">OK</strong>.<p id="css_01_0153__p12730547141714">During data migration, the system migrates all data from the to-be-removed nodes to the remaining nodes, and removes these nodes upon completion of the data migration. If the data on the to-be-removed nodes has replicas on other nodes, data migration can be skipped and the cluster change can be completed faster.</p>
</li><li id="css_01_0153__en-us_topic_0000001338468977_li13737436141418">Click <span class="uicontrol" id="css_01_0153__uicontrol1184557618"><b>Back to Cluster List</b></span> to switch to the <strong id="css_01_0153__b1527787975">Clusters</strong> page. The <span class="parmname" id="css_01_0153__parmname1802806021"><b>Task Status</b></span> is <span class="parmvalue" id="css_01_0153__parmvalue1471509348"><b>Scaling in</b></span>. When <span class="parmname" id="css_01_0153__parmname1482437277"><b>Cluster Status</b></span> changes to <span class="parmvalue" id="css_01_0153__parmvalue2137308736"><b>Available</b></span>, the cluster has been successfully scaled in.</li></ol>
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<div class="parentlink"><strong>Parent topic:</strong> <a href="css_01_0414.html">Scaling an Elasticsearch Cluster</a></div>
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