---
title: "Differences between MySQL sync and MySQL semi-sync"
sidebar_label: "Differences between MySQL sync and MySQL semi-sync"
sidebar_position: 1
description: "Differences between MySQL sync and MySQL semi-sync DBMSs"
---

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# Differences between MySQL sync and MySQL semi-sync

Managed Databases support [MySQL sync](/managed-databases/mysql-sync/) and [MySQL semi-sync](/managed-databases/mysql-semi-sync/). The table below shows the differences between them.

<CustomTable>
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    <thead>
      <tr>
        <th />

        <th>MySQL synchronous replication</th><th>MySQL semi-synchronous replication</th>
      </tr>
    </thead>

    <tbody>
      <tr>
        <th>Replication</th><td>Multi-master (synchronous) — requires all replicas to receive data for write confirmation</td>

        <td>
          Master-replica (semi-synchronous) — requires at least one replica to receive data for write confirmation
        </td>
      </tr>

      <tr>
        <th>Fault tolerance</th><td>You can create a cluster without replicas or with only two replicas</td><td>You can create a cluster without replicas, with one, or with two replicas</td>
      </tr>

      <tr>
        <th>Limitations</th>

        <td>
          Fault-tolerant clusters with replicas are subject to [limitations](/managed-databases/mysql-sync/limitations.mdx)
        </td>

        <td>No limitations</td>
      </tr>

      <tr>
        <th>Connecting to the cluster</th><td>Port 6033 is used to connect to ProxySQL</td><td>Port 3306 is used to connect to the cluster</td>
      </tr>
    </tbody>
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