migration from cyrus 2.0.16 to cyrus 2.1.14

[toskala]

Hi, 

i am completely stuck with the migration process from cyrus 2.0.16 to 
2.1.14. 

i sucessfully migrated the /var/imap/mailbox.db from the old flat style to 
the new db3 style.
when i restarted cyrus 2.1.14 and choose cyradm --user cyrus localhost i get 
a complete userlist when i type "lm". 

the problem is to migrate all user mailboxes. i wasnt able to find a good 
documentation that allows me to follow step by step, is there such a howto? 

the mailinglists tell me that i should create a dump of the database, 
convert it, tar all old mail, put on the new server, untar it, run 
reconstruct and be happy, but it doesnt seem to be that easy. 

but reconstruct just states "unknown/invalid partition". 

i had a closer look to my /etc/imapd.conf and it points to the correct 
directories. 

i would love to get a little step by step thing on how to accomplish the 
migration. 

thanks in advance,
markus 

p.s. some people told me that the only way they got migration working was 
copying the mails via a mailclient, hell, its about 100users here :)