IMAP Alternate partition problem

Question

IMAP partition problem
IMAP is set so all boxes are on a separate partition ..
and until recently, worked fine.
one day (shortly after 10.4.9 upgrade)
after "rebuilding" an IMAP inbox from Mail.app
everything went down.. and came up again with all IMAP boxes other than INBOX appearing gone
but what happened is that all the accounts suddenly reverted (?) to existing on the default partition (var/spool/imap)
and although the alternate partition still exists and all settings reflect such..
I can't get the accounts back to seeing that partition.
cyradmn does not 'see' boxes on the alt partition.
thus, I cant retrieve some huge folders of stored mail.
in addition, the accounts are unable to create any folders on the current (default) partition and only "inbox" exists (no Sent or Drafts, etc..).
(the error returned : System I/O error)
mail works, can send and receive, .. but how to restore accounts to the alternate partition ??
Ive tried shutting off the account and deleting the user mailbox (on default partition) and turning back on the user.. still creates on the default partition
the accounts still show (in SA and NetInfo record) set to alternate partition..
and imapd.conf still has the partition entry ..
what's up ??

Answer 1

Thanks for the responses ..
yes, actually, I have tried reconstruct from mailbfr (options -o and -m) as well as via cyradm.. and SA
either option succeeds at reconstructing all the boxes fine, and permissions appear to be fine as well..
drwxr-xr-x 4 cyrusima mail - 136B Jun 3 2006 mailstore
mailbfr reports both partitions being operated on ..
my config also appears OK, its the same as has been working flawlessly for over a year :
admins: cyrusimap localadmin
configdirectory: /var/imap
partition-default: /var/spool/imap
unixhierarchysep: yes
altnamespace: yes
servername: mail.mydomain.com
sievedir: /usr/sieve
sendmail: /usr/sbin/sendmail
lmtpdowncasercpt: 1
tlscertfile: /etc/certificates/mail.mydomain.com.crt
logrollingdays: 0
logrolling_daysenabled: false
tlskeyfile: /etc/certificates/mail.mydomain.com.key
imapauth_crammd5: yes
imapauthgssapi: yes
popauthclear: no
enable_pop: no
tlscommonname: mail.mydomain.com
tlsserveroptions: use
imapauthlogin: yes
partition-mailstore: /Volumes/path/to/alt-partition
I did notice an odd thing though..
although the boxes are being read from /var/spool/imap
and accounts show "default" partition (in SA)
when I try to create a box (via Mail.app) in IMAP acct..
it fails .. can't so it ..
and the IMAP log shows
imaps[22176]: IOERROR: creating directory /Volumes/path/to/alt-partition: Permission denied
so it appears to want to write to the right place and can't ..
but still reads from the wrong place.
something is amiss !!
where to look next ?