Are there any technical requirements for migration performance?

There are no universal technical requirements for all the stores as different platforms have different technical peculiarities. However, there are some recommendations you should consider before setting shopping cart migration.

Recommended PHP configurations:

memory_limit - 128M (512M for Magento)
post_max_size - 16M
max_execution_time - 60

If Suhosin module is installed:

suhosin.post.max_value_length - 16777216
suhosin.request.max_value_length - 16777216

Also, it is advisable to switch off the limits for the number of requests to server, as well as firewalls and basic authentication.