[Dovecot] doveadm purge on shared storage

We've finally (!) started to put some users on mdbox instead of maildir, and now I'm wondering about the purge step. As we're running GPFS for the mailboxes (and dovecot director in front of every dovecot service), is it important to run the "doveadm purge -u $user" on the same host as $user is logged into to avoid index corruption ?

If so, will we need to run the "doveadm purge" trough the dovecot director as well?

-jf