what is the best way to migrate old drupal user database to new drupal install?

Hi,

what do you mean with more safe?
You create a backup! This is the safest way you can go.
If something goes wrong you can always fall back. This is the meaning of backup.
Drupal is nothing more than files in one folder and a database.

Roi

I'm a noob, but I'll tell you what I think.

First, I'm assuming you're talking about moving users from a current v5.x install to a new v5.x install
(as opposed to moving v4.x users to a v5.x install or v5.x users to a v6.x install)...

> backup and migrate

With regard to migrating, the B&M module doesn't do anything that phpmyadmin can't do. If you're used to using phpmyadmin, then I would personally find it easier to export only the user-related tables and import them into the new installation using phpmyadmin. However B&M does allow you to back-up only selected tables too (at least, it does in v6.x) but the selection of them is a bit fiddly.

B&M's real power is allowing users to create an archive of daily backups without messing about with separate bash-scripts and cron-jobs. But in the case of a failure, like a 'white screen of death', you're probably not going to be able access the B&M module to import the back-ups, so it might be worth learning how to import/export using phpmyadmin anyway.

Whichever method you use, you'd need to think carefully about which user information you import. For instance, if you only imported the table: 'users', what would happen to the information about their profiles, roles, permissions and sessions? So you *might* also have to import other user-related tables, such as:

users_roles
sessions
role
authmap <--- I don't actually know what this does, but it sounds user-related!
permission
profile_fields
profile_values

(NB. these tables are from my D6 install. They might not be present in your D5 install).

Whatever you do, as Roi said, perfrom a full backup of your new install before doing anything, and you will be able to get back to where you started if anything goes wrong (although it's a new, clean install, so you're probably only ten minutes away from disaster recovery anyway).

Good luck.
Tell us if anything unexpected happens: I'll need to do this myself at some point in the future.

The one other thing that has to be done is update the UID part of your sequence table to match your highest UID. Or else when you or someone tries to make an account you will get "duplicate entry" error.