Is there a time limit for the execution of a custom workflow (or any other limit)

Hi,

I need an option for generating a large amount of records for CRM Online, and we have to choose the technology.

So far we tested generating the records with a plugin, but the execution time is limited to 2 minutes and it didn't work. 

We are wondering whether we can use a custom workflow activity to generate the records, 

but we don't want to test it in vain, so can you tell me what are the limits of the custom workflow activity?

If you have any other suggestion for a built-in CRM functionality, please share.

We have considered writing a custom service to generate the records, but we believe that using a built-in functionality will be faster.

Thanks.

Best regards,

Evgeni Dyulgerov