<!-- 
RSS generated by JIRA (9.7.1#970001-sha1:2222b88b221c4928ef0de3161136cc90c8356a66) at Thu Feb 08 07:48:46 UTC 2024

It is possible to restrict the fields that are returned in this document by specifying the 'field' parameter in your request.
For example, to request only the issue key and summary append 'field=key&field=summary' to the URL of your request.
-->
<rss version="0.92" >
<channel>
    <title>MongoDB Jira</title>
    <link>https://jira.mongodb.org</link>
    <description>This file is an XML representation of an issue</description>
    <language>en-us</language>    <build-info>
        <version>9.7.1</version>
        <build-number>970001</build-number>
        <build-date>13-04-2023</build-date>
    </build-info>


<item>
            <title>[DOCS-4748] Document the process for calculating oplog size</title>
                <link>https://jira.mongodb.org/browse/DOCS-4748</link>
                <project id="10380" key="DOCS">Documentation</project>
                    <description>&lt;p&gt;Replication oplog window should cover normal maintenance/downtime windows (to avoid full resync), and also time needed to restore a RS member (either time needed for initial sync, or time to restore the last backup so it will not become stale). &lt;/p&gt;

&lt;p&gt;To estimate the size you should look at the oplog rate (oplog GB/h graph in MMS or use the db.printReplicationInfo() output) &lt;em&gt;at it&apos;s maximum&lt;/em&gt; (i.e. during the load peak).&lt;/p&gt;

&lt;p&gt;The default oplog size should never be used without consideration.&lt;/p&gt;

&lt;p&gt;For the sake of example, let&apos;s say my system has the following timings:&lt;/p&gt;
&lt;ul&gt;
	&lt;li&gt;usual maintenance window: 24 hours&lt;/li&gt;
	&lt;li&gt;time to restore a backup is 3 hours&lt;/li&gt;
	&lt;li&gt;backups are taken every 24 hours&lt;/li&gt;
	&lt;li&gt;time needed for an initial sync: 6 hours&lt;/li&gt;
	&lt;li&gt;oplog rate is 3 GB/h at peak time&lt;/li&gt;
&lt;/ul&gt;


&lt;p&gt;Here I would need to cover at least 24 hours for the usual maintenance window (it also covers the time needed for an initial sync, which is 6 hours). However, if I were to restore a backup that is 24 hours behind, and the restore process takes 3 hours, I would need at least 27 hours in the oplog to allow the restored replica set member to catch up.&lt;/p&gt;

&lt;p&gt;It&apos;s practical to round it up to 36 hours, which is 108GB at the 3 GB/h rate. Further, it makes sense to account for sudden load spikes and some future growth of the oplog rate, so I would use 200GB instead.&lt;/p&gt;

&lt;p&gt;cc &lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=richard%4010gen.com&quot; class=&quot;user-hover&quot; rel=&quot;richard@10gen.com&quot;&gt;richard@10gen.com&lt;/a&gt;&lt;/p&gt;</description>
                <environment>Probably on the oplog resize page or on prod notes</environment>
        <key id="181744">DOCS-4748</key>
            <summary>Document the process for calculating oplog size</summary>
                <type id="3" iconUrl="https://jira.mongodb.org/secure/viewavatar?size=xsmall&amp;avatarId=14718&amp;avatarType=issuetype">Task</type>
                                            <priority id="3" iconUrl="https://jira.mongodb.org/images/icons/priorities/major.svg">Major - P3</priority>
                        <status id="6" iconUrl="https://jira.mongodb.org/images/icons/statuses/closed.png" description="The issue is considered finished, the resolution is correct. Issues which are closed can be reopened.">Closed</status>
                    <statusCategory id="3" key="done" colorName="success"/>
                                    <resolution id="2">Won&apos;t Fix</resolution>
                                        <assignee username="-1">Unassigned</assignee>
                                    <reporter username="alex.komyagin@mongodb.com">Alexander Komyagin</reporter>
                        <labels>
                    </labels>
                <created>Fri, 30 Jan 2015 20:12:14 +0000</created>
                <updated>Mon, 30 Oct 2023 21:49:19 +0000</updated>
                            <resolved>Tue, 1 Nov 2022 11:03:02 +0000</resolved>
                                                    <fixVersion>Server_Docs_20231030</fixVersion>
                                    <component>manual</component>
                    <component>Server</component>
                        <due></due>
                            <votes>0</votes>
                                    <watches>9</watches>
                                                                                                                <comments>
                            <comment id="4943692" author="edu.bot" created="Tue, 1 Nov 2022 11:02:59 +0000"  >&lt;p&gt;Hello! This ticket has been closed due to inactivity. If you believe this ticket is still important, please reopen it and leave a comment to explain why. Thank you!&lt;/p&gt;</comment>
                            <comment id="2492964" author="daniel.coupal" created="Mon, 21 Oct 2019 16:59:06 +0000"  >&lt;p&gt;As for a lot of cases, it depends, however you are right that 3-5 days would be the minimum to suggest to a customer.&lt;/p&gt;</comment>
                            <comment id="2492424" author="nicholas.cottrell" created="Mon, 21 Oct 2019 13:37:25 +0000"  >&lt;p&gt;&lt;a href=&quot;https://jira.mongodb.org/secure/ViewProfile.jspa?name=daniel.coupal&quot; class=&quot;user-hover&quot; rel=&quot;daniel.coupal&quot;&gt;daniel.coupal&lt;/a&gt;&#160; - when you ran NHTT, the rule of thumb was always 72 hours to allow for weekend downtime, right?&#160; I guess we could say&lt;/p&gt;
&lt;blockquote&gt;&lt;p&gt;max(usual maintenance window, weekend): 64 hours&lt;/p&gt;&lt;/blockquote&gt;</comment>
                    </comments>
                    <attachments>
                    </attachments>
                <subtasks>
                    </subtasks>
                <customfields>
                                                <customfield id="customfield_10050" key="com.atlassian.jira.toolkit:comments">
                        <customfieldname># Replies</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>3.0</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        <customfield id="customfield_10055" key="com.atlassian.jira.ext.charting:firstresponsedate">
                        <customfieldname>Date of 1st Reply</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>Sat, 24 Sep 2016 18:23:11 +0000</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_10052" key="com.atlassian.jira.toolkit:dayslastcommented">
                        <customfieldname>Days since reply</customfieldname>
                        <customfieldvalues>
                                        1 year, 14 weeks, 1 day ago
    
                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_18254" key="com.onresolve.jira.groovy.groovyrunner:scripted-field">
                        <customfieldname>Dependencies</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue><![CDATA[]]></customfieldvalue>


                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_15850" key="com.atlassian.jira.plugins.jira-development-integration-plugin:devsummary">
                        <customfieldname>Development</customfieldname>
                        <customfieldvalues>
                            
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                            <customfield id="customfield_10857" key="com.pyxis.greenhopper.jira:gh-epic-link">
                        <customfieldname>Epic Link</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>DOCSP-1769</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            <customfield id="customfield_10057" key="com.atlassian.jira.toolkit:lastusercommented">
                        <customfieldname>Last comment by Customer</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>false</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_10056" key="com.atlassian.jira.toolkit:lastupdaterorcommenter">
                        <customfieldname>Last commenter</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>emet.ozar@mongodb.com</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_11151" key="com.atlassian.jira.toolkit:LastCommentDate">
                        <customfieldname>Last public comment date</customfieldname>
                        <customfieldvalues>
                            1 year, 14 weeks, 1 day ago
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                            <customfield id="customfield_10051" key="com.atlassian.jira.toolkit:participants">
                        <customfieldname>Participants</customfieldname>
                        <customfieldvalues>
                                        <customfieldvalue>alex.komyagin@mongodb.com</customfieldvalue>
            <customfieldvalue>daniel.coupal@mongodb.com</customfieldvalue>
            <customfieldvalue>edu.bot</customfieldvalue>
            <customfieldvalue>nicholas.cottrell@mongodb.com</customfieldvalue>
    
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                        <customfield id="customfield_14254" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>Product Rank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>1|hrqk3z:</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                <customfield id="customfield_12550" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>Rank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>2|hsq7gv:</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                <customfield id="customfield_10558" key="com.pyxis.greenhopper.jira:gh-global-rank">
                        <customfieldname>Rank (Obsolete)</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>159681</customfieldvalue>
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    <customfield id="customfield_10053" key="com.atlassian.jira.ext.charting:timeinstatus">
                        <customfieldname>Time In Status</customfieldname>
                        <customfieldvalues>
                            
                        </customfieldvalues>
                    </customfield>
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            <customfield id="customfield_14350" key="com.pyxis.greenhopper.jira:gh-lexo-rank">
                        <customfieldname>serverRank</customfieldname>
                        <customfieldvalues>
                            <customfieldvalue>1|hrz51b:</customfieldvalue>

                        </customfieldvalues>
                    </customfield>
                                                                </customfields>
    </item>
</channel>
</rss>