ok, I installed zstd successfully, it works - but how i re-compress everything via dsync ? (on the same server?)

I did :

sudo doveadm backup -D -u "${mailbox_username}" "mdbox:/home/vmail/virtualmailboxes/${mailbox_username}_backup"
sudo service dovecot stop
sudo mv "/home/vmail/virtualmailboxes/${mailbox_username}" "/home/vmail/virtualmailboxes/${mailbox_username}_original"
sudo mv "/home/vmail/virtualmailboxes/${mailbox_username}_backup" "/home/vmail/virtualmailboxes/${mailbox_username}"
sudo service dovecot start

but somehow that does not work correctly, thunderbird claims that mailboxes are not existing, etc ...

so what is the correct way to recompress the mailboxes locally ?

Robert





Am 28.08.2020 um 13:15 schrieb Timo Sirainen:
On 28. Aug 2020, at 12.10, Robert Nowotny <rnowotny@rotek.at> wrote:

unfortunately after re-installing 2.3.11.3, those broken-pipe errors appear again. (on different, new files)
so for sure there is something broken with zlib.
I will go back to 2.3.10.1 now.
attached is the configuration file, though it did not change between 2.3.10.1 and 2.3.11.3

Oh, this is with xz, not with gz like we first thought. There are some known problems with xz, which is why we are planning on removing it entirely. I'm not sure why v2.3.11 breaks it, although there are some changes related to it but it might be coincidence. I can't reproduce this problem though.

In any case, I'd recommend switching to zlib or to zstd in v2.3.12. (In theory you could leave the existing mails xz-compressed, but best would be to re-compress everything via dsync so old mails can be read when we eventually remove xz support.)