Magento – How to migrate the data from Magento 1.9 to Magento 2.1

Default Magento 2 Migration tool.

Guide Link : http://devdocs.magento.com/guides/v2.0/migration/bk-migration-guide.html

Install tool for a migration : https://github.com/magento/data-migration-tool/

OR

UberTheme migration tool.

This is easier way to migrate Magento 1.9.X to Magento 2.X.X

Guide Link : https://www.ubertheme.com/magento-news/magento-2-data-migration-pro-release/

Install tool for a migration : https://github.com/ubertheme/magento2_data_migration/releases/tag/Version0.1.0

Yes, it is possible but you will have to modify a bit the config files to get what you need.

Here is an example of the Data Migration Tool config.xml used to migrate only customers and newsletters subscribers.

<?xml version="1.0" encoding="UTF-8"?>
<config xmlns:xs="http://www.w3.org/2001/XMLSchema-instance" xs:noNamespaceSchemaLocation="../../config.xsd">
<steps mode="data">
    <step title="Data Integrity Step">
        <integrity>Migration\Step\DataIntegrity\Integrity</integrity>
    </step>
    <step title="Customer Attributes Step">
        <integrity>Migration\Step\Customer\Integrity</integrity>
        <data>Migration\Step\Customer\Data</data>
        <volume>Migration\Step\Customer\Volume</volume>
    </step>
    <step title="Newsletter Subscribers Step">
        <integrity>Migration\Step\Newsletter\Integrity</integrity>
        <data>Migration\Step\Newsletter\Data</data>
        <volume>Migration\Step\Newsletter\Volume</volume>
    </step>
</steps>
<steps mode="delta">
    <step title="Customer Attributes Step">
        <delta>Migration\Step\Customer\Delta</delta>
        <volume>Migration\Step\Customer\Volume</volume>
    </step>
</steps>
<source>
    <database host="172.x.x.x" name="source-db-name" user="dbuser" password="dbpassword"/>
</source>
<destination>
    <database host="172.x.x.x" name="source-db-name" user="dbuser" password="dbpassword"/>
</destination>
<options>
    <map_file>etc/ce-to-ee/1.7.0.0/map.xml</map_file>
    <customer_map_file>etc/ce-to-ee/map-customer.xml</customer_map_file>
    <customer_document_groups_file>etc/ce-to-ee/customer-document-groups.xml.dist</customer_document_groups_file>
    <customer_attribute_groups_file>etc/ce-to-ee/customer-attribute-groups.xml.dist</customer_attribute_groups_file>
    <delta_document_groups_file>etc/ce-to-ee/deltalog.xml</delta_document_groups_file>
    <map_document_groups>etc/ce-to-ee/map-document-groups.xml.dist</map_document_groups>
    <bulk_size>0</bulk_size>
    <direct_document_copy>0</direct_document_copy>
    <source_prefix />
    <dest_prefix />
    <auto_resolve_urlrewrite_duplicates>0</auto_resolve_urlrewrite_duplicates>
    <log_file>migration.log</log_file>
    <progress_bar_format>%percent%% [%bar%] Remaining Time: %remaining%</progress_bar_format>
    <upgrade_customer_password_hash>1</upgrade_customer_password_hash>
    <edition_migrate>ce-to-ee</edition_migrate>
    <edition_number>1.7.0.0</edition_number>
    <init_statements_source>SET NAMES utf8;</init_statements_source>
    <init_statements_destination>SET NAMES utf8;</init_statements_destination>
    <crypt_key>xxxxxxxxpatataxxxxxxxxxx</crypt_key>
</options>

In this example you can see how all unnecessary steps have been removed to leave only Customer Attributes Step which is in charge of customer migration.

Newsletter Subscribers Step is a custom step created to migrate specific data.

You can use this example to modify your config.xml file and migrate only customers and sales data.

Hope it helps.