Inserting additional entries after migrating from 1.9.1.0 to 2.1.6

Question

I have already successfully migrated the contents of a site from 1.9.1.0 to 2.1.6 using the official migration module but the old site hasn't been taken down and the new site hasn't gone live so new entries are still being added to the old site. I tried resuming the migration but if I use the -r option, I keep getting one of the following errors alternately:

SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '1-Migration_Default' for key 'EAV_ATTRIBUTE_SET_ENTITY_TYPE_ID_ATTRIBUTE_SET_NAME'

Notice: Undefined offset: 1 in /var/www/html/peppy/smappliance/vendor/magento/data-migration-tool/src/Migration/Step/Eav/Data.php on line 283

and if I don't use -r, the migration completes but nothing gets added. How can I resume migration? Thanks.

Answer 1

There is three type of migration:

1. Settings: Migrates the system configuration and website-related settings
2. Data: Migrates database assets in bulk
3. Delta: Migrates incremental changes (for example, orders and inventory)

So you have to use delta migration using command bin/magento migrate:delta [-r|--reset] {<path to config.xml>}

for more ref : http://devdocs.magento.com/guides/v2.0/migration/migration-migrate-delta.html