Corrupted index cache file - migration with zlib

[Leon Kyneur]

Hi

I'm migrating some mailboxes from an old dovecot system where mailboxes are
stored maildir uncompressed. I enabled zlib on the new system and migrated
an account:
doveadm -o mail_fsync=never backup -R -u tonyg imapc:

when the account connects to the new system after a while i'm seeing the
following error and the mailbox is no longer functioning:

Jan 15 13:58:06 S611 dovecot: imap(tonyg): Error:
read(/srv/vmail/532868/tonyg/mdbox/storage/m.1): FETCH BODY[] for mailbox
INBOX UID 61 got too little data: 4106341 vs 6054268
Jan 15 13:58:06 S611 dovecot: imap(tonyg): Error:
unlink(/srv/vmail/532868/tonyg/mdbox/mailboxes/INBOX/dbox-Mails/dovecot.index.cache)
failed: No such file or directory (in mail-cache.c:28)
Jan 15 13:58:06 S611 dovecot: imap(tonyg): Error: Corrupted index cache
file
/srv/vmail/532868/tonyg/mdbox/mailboxes/INBOX/dbox-Mails/dovecot.index.cache:
Broken virtual size for mail UID 61
Jan 15 13:58:06 S611 dovecot: imap(tonyg): FETCH failed in=181 out=4109653
Jan 15 13:58:06 S611 dovecot: auth-worker(6130): ldap(tonyg,144.132.1.90):
unknown user
Jan 15 13:58:06 S611 dovecot: imap-login: Login: user=<tonyg>,
method=PLAIN, rip=144.132.1.90, lip=203.134.11.127, mpid=6746, secured,
session=<7qqWklYpnGjLhgHK>
Jan 15 13:58:07 S611 dovecot: imap(tonyg): Error:
read(/srv/vmail/532868/tonyg/mdbox/storage/m.1): FETCH BODY[] for mailbox
INBOX UID 61 got too little data: 4106341 vs 6054268
Jan 15 13:58:07 S611 dovecot: imap(tonyg): Error:
unlink(/srv/vmail/532868/tonyg/mdbox/mailboxes/INBOX/dbox-Mails/dovecot.index.cache)
failed: No such file or directory (in mail-cache.c:28)
Jan 15 13:58:07 S611 dovecot: imap(tonyg): Error: Corrupted index cache
file
/srv/vmail/532868/tonyg/mdbox/mailboxes/INBOX/dbox-Mails/dovecot.index.cache:
Broken virtual size for mail UID 61
Jan 15 13:58:07 S611 dovecot: imap(tonyg): FETCH failed in=181 out=4109653

If i migrate the account without zlib everthing works fine and the error
can't be reproduced.

I have tried force-resync and index commands to no avail.

Any ideas what's going on here?

doveconf -n:

[root at S611 532868]# doveconf -n


# 2.2.21 (5345f22): /etc/dovecot/dovecot.conf
# Pigeonhole version 0.4.11 (6ddf62b87f60+)
# OS: Linux 3.10.0-327.4.4.el7.x86_64 x86_64 CentOS Linux release 7.2.1511
(Core)
auth_debug = yes
auth_verbose = yes
imapc_features = rfc822.size fetch-headers
imapc_host = removed
imapc_master_user = removed
imapc_password =  # hidden, use -P to show it
imapc_user = %u
lmtp_proxy = yes
login_trusted_networks = 192.168.10.0/24
mail_debug = yes
mail_gid = vmail
mail_location = mdbox:%h/mdbox:ALT=/altstorage%h/mdbox
mail_plugins = quota zlib
mail_prefetch_count = 50
mail_uid = vmail
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope encoded-character
vacation subaddress comparator-i;ascii-numeric relational regex imap4flags
copy include variables body enotify environment mailbox date
 index ihave duplicate mime foreverypart
mdbox_rotate_size = 10 M
namespace inbox {
  inbox = yes
  location =
  mailbox "Deleted Messages" {
    special_use = \Trash
  }
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  prefix =
}
passdb {
  args = /etc/dovecot/dovecot-ldap.conf.ext
  driver = ldap
}
passdb {
  args = /etc/dovecot/dovecot-ldap-m2core.conf.ext
  driver = ldap
}
plugin {
  quota = dict:User quota::file:%h/dovecot-quota
  sieve = file:~/sieve;active=~/.dovecot.sieve
  zlib_save = gz
  zlib_save_level = 6
}
pop3c_host = <removed>
pop3c_password =  # hidden, use -P to show it
service lmtp {
  inet_listener lmtp {
    address = <removed>
    port = 24
  }
}
ssl_cert = </etc/pki/dovecot/certs/dovecot.pem
ssl_key = </etc/pki/dovecot/private/dovecot.pem
verbose_proctitle = yes
protocol imap {
  mail_plugins = quota imap_quota imap_zlib
}