diff --git a/pulsar-client-tools/src/main/java/org/apache/pulsar/admin/cli/CmdNamespaces.java b/pulsar-client-tools/src/main/java/org/apache/pulsar/admin/cli/CmdNamespaces.java
index 6614e44b9a8c7..c825397b8d84c 100644
--- a/pulsar-client-tools/src/main/java/org/apache/pulsar/admin/cli/CmdNamespaces.java
+++ b/pulsar-client-tools/src/main/java/org/apache/pulsar/admin/cli/CmdNamespaces.java
@@ -752,8 +752,8 @@ private class SetRetention extends CliCommand {
                 + "For example, 4096, 10M, 16G, 3T.  The size unit suffix character can be k/K, m/M, g/G, or t/T.  "
                 + "If the size unit suffix is not specified, the default unit is bytes. "
                 + "0 or less than 1MB means no retention and -1 means infinite size retention", required = true,
-                converter = ByteUnitIntegerConverter.class)
-        private Integer sizeLimit;
+                converter = ByteUnitToLongConverter.class)
+        private Long sizeLimit;
 
         @Override
         void run() throws PulsarAdminException {
@@ -761,8 +761,8 @@ void run() throws PulsarAdminException {
             final int retentionTimeInMin = retentionTimeInSec !=  -1
                     ? (int) TimeUnit.SECONDS.toMinutes(retentionTimeInSec)
                     : retentionTimeInSec.intValue();
-            final int retentionSizeInMB = sizeLimit != -1
-                    ? (int) (sizeLimit / (1024 * 1024))
+            final long retentionSizeInMB = sizeLimit != -1
+                    ? (sizeLimit / (1024 * 1024))
                     : sizeLimit;
             getAdmin().namespaces()
                     .setRetention(namespace, new RetentionPolicies(retentionTimeInMin, retentionSizeInMB));
diff --git a/pulsar-client-tools/src/test/java/org/apache/pulsar/admin/cli/TestCmdNamespaces.java b/pulsar-client-tools/src/test/java/org/apache/pulsar/admin/cli/TestCmdNamespaces.java
new file mode 100644
index 0000000000000..f9ce84411c6c0
--- /dev/null
+++ b/pulsar-client-tools/src/test/java/org/apache/pulsar/admin/cli/TestCmdNamespaces.java
@@ -0,0 +1,52 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pulsar.admin.cli;
+
+import org.apache.pulsar.client.admin.Namespaces;
+import org.apache.pulsar.client.admin.PulsarAdmin;
+import org.apache.pulsar.common.policies.data.RetentionPolicies;
+import org.testng.annotations.AfterMethod;
+import org.testng.annotations.Test;
+import java.io.IOException;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class TestCmdNamespaces {
+
+    @AfterMethod(alwaysRun = true)
+    public void cleanup() throws IOException {
+        //NOTHING FOR NOW
+    }
+
+
+    @Test
+    public void testSetRetentionCmd() throws Exception {
+        Namespaces namespaces = mock(Namespaces.class);
+
+        PulsarAdmin admin = mock(PulsarAdmin.class);
+        when(admin.namespaces()).thenReturn(namespaces);
+
+        CmdNamespaces cmd = new CmdNamespaces(() -> admin);
+
+        cmd.run("set-retention public/default -s 2T -t 2h".split("\\s+"));
+        verify(namespaces, times(1)).setRetention("public/default", new RetentionPolicies(120, 2 * 1024 * 1024));
+   }
+}