Hi,
I'm running dovecot 2.3.13 (until 05.01. it was 2.3.11.3) on Arch Linux and used lzma compressed mdboxes. Yesterday a user called me that she is missing all mails from the beginning of the month until now. I took a look into the logs and saw several "lzma.read [...] unexpected EOF at <....>". As I had no clue why the mdboxes are broken, I tried to convert all 3 mailboxes to Maildir using "doveadm sync" to prevent further issues and stumbled upon several lzma errors for mdbox files of my own user. So I wrote a script which took the offset and size via "doveadm dump" und then dds the xz parts out of the broken mdboxes and extracts them via 7z.
But I'm wondering why that happened at all. I stumpled upon [1] but there was no further discussion about it.
Best Regards Bjoern
[1]https://dovecot.org/pipermail/dovecot/2019-September/117007.html