Backup questions - errors

Mark Patruck mark at
Fri Aug 28 10:54:19 EEST 2020


although i've search the archives, there are questions left regarding
backup strategies and errors that occur.

I'm using dovecot with mdbox (mailbox size 50MB - 30GB).

Every night, i ran the following command:

doveadm -o mail_fsync=never -o plugin/quota= -o plugin/zlib_save=gz \
	backup -u account mdbox:/nfs/storage/account/mdbox

### incremental backup
Thanks to zlib compression, i save a lot of storage space, nonetheless
i'd go with an incremental backup, but it seems to only merge changes,
comparing to rsyncs' --link-dest option where you can put all "changes
of the day" in an extra folder. I'd like to prevent loosing mail that
gets deleted by accident/on purpose. How can i achieve this with dsync
and w/o doing a full backup every day?

### backup errors
After a few days w/o any errors, doveadm prints the following lines (only
for the biggest, 30GB mailbox) two days in a row. As dovecot has self-
healing capabilities, i think these errors/warnings can be ignored and
should go away...?

Error: Transaction log ....mdbox/dovecot.list.index.log: duplicate transaction log sequence (38)
Error: Index ....mdbox/dovecot.list.index: Lost log for seq=38 offset=63312: Missing middle file 
seq=38 (between 38..4294967295, we have seqs 37,39): .log.2 contains file_seq=37 (initial_mapped=1, 
reason=Index mapped)
Warning: fscking index file ....mdbox/dovecot.list.index
Error: Fixed index file ....mdbox/dovecot.list.index: log_file_seq 38 -> 39
Error: Mailbox list index was marked as fsck'd ....mdbox/dovecot.list.index
Error: Mailbox list index was marked as fsck'd ....mdbox/dovecot.list.index
Error: Mailbox list index was marked as fsck'd ....mdbox/dovecot.list.index



Mark Patruck ( mark at )
GPG key 0xF2865E51 / 187F F6D3 EE04 1DCE 1C74  F644 0D3C F66F F286 5E51

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