I'm attaching you an example :)
#!/bin/sh
#VERSION=0.0.2
# This script is written by Martynas Bendorius and DirectAdmin
# It is used to gzip all emails in Maildir directory
# Official DirectAdmin webpage: http://www.directadmin.com
# Usage:
# ./dovecot_compress.sh </home/user/imap/domains/domain.com/email/Maildir>
MYUID=`/usr/bin/id -u`
if [ "${MYUID}" != 0 ]; then
echo "You require Root Access to run this script";
exit 0;
fi
if [ $# -lt 1 ]; then
echo "Usage:";
echo "$0 /home/user/imap/domains/domain.com/email/Maildir";
echo "you gave #$#: $0 $1";
exit 0;
fi
MAILDIR_PATH="${1}"
if ! echo "${MAILDIR_PATH}" | grep -m1 -q '/Maildir$'; then
echo "Path does not end with /Maildir: ${MAILDIR_PATH}. Exiting.."
exit 1
fi
if [ ! -d "${MAILDIR_PATH}/cur" ]; then
echo "${MAILDIR_PATH}/cur does not exist, exiting..."
exit 1
fi
cd "${MAILDIR_PATH}"
if [ $? -ne 0 ]; then
echo "Failed to cd to ${MAILDIR_PATH}. Exiting..."
exit 1
fi
echo "Checking for directories in ${MAILDIR_PATH}..."
# https://wiki.dovecot.org/Plugins/Zlib
find . -maxdepth 1 -mindepth 1 -type d -print0 | while read -d $'\0' directory;
do {
if [ "${directory}" = "tmp" ]; then
continue
fi
cd "${MAILDIR_PATH}/${directory}"
if [ $? -ne 0 ]; then
echo "Failed to cd to ${MAILDIR_PATH}/${directory}. Skipping..."
continue
fi
if [ ! -d "${MAILDIR_PATH}/${directory}/tmp" ]; then
mkdir -p ${MAILDIR_PATH}/${directory}/tmp
chown --reference=${MAILDIR_PATH}/${directory}
${MAILDIR_PATH}/${directory}/tmp
fi
find ./tmp/ -maxdepth 1 -group mail -type f -delete
# ignore all files with "*,S=*" (dovecot needs to know the size of the
email, when it's gzipped) and "*,*:2,*,*Z*" (dovecot recommends adding Z to the
end of gzipped files just to know which ones are gzipped) in their names, also
skip files that are also compressed (find skips all other 'exec' after first
failure)
# dovecot: Note that if the filename doesn't contain the ',S=<size>'
before compression, adding it afterwards changes the base filename and thus the
message UID. The safest thing to do is simply to not compress such files.
find . -type f -name "*,S=*" ! -name "*,*:2,*,*Z*" ! -exec gzip -t {}
2>/dev/null \; -exec sh -c 'gzip --best --stdout $1 > ./tmp/$1' x {} \; -exec
sh -c 'chown --reference=$1 ./tmp/$1' x {} \; -exec sh -c 'chmod --reference=$1
./tmp/$1' x {} \; -exec sh -c 'touch --reference=$1 ./tmp/$1' x {} \;
#if there are any compressed files, maildirlock the directory
if ! find ./tmp -maxdepth 0 -type d -empty | grep -m1 -q '\.'; then
echo "Size before compression: `du -sh
\"${MAILDIR_PATH}/${directory}\" | awk '{print $1}'`"
MAILDIRLOCK=/usr/libexec/dovecot/maildirlock
if [ ! -x ${MAILDIRLOCK} ]; then
MAILDIRLOCK=/usr/lib/dovecot/maildirlock
fi
if [ ! -x ${MAILDIRLOCK} ]; then
echo "Unable to find ${MAILDIRLOCK}, exiting..."
find ./tmp/ -maxdepth 1 -group mail -type f -delete
exit 2
fi
# If we're able to create the maildirlock, then continue with
moving compressed emails back
#MAILDIRLOCK had a bug, which is patched in CB 2.0
if PIDOFMAILDIRLOCK=`${MAILDIRLOCK}
"${MAILDIR_PATH}/${directory}" 10`; then
# Move email only if it exists in destination folder,
otherwise it's been removed at the time we converted it
find ${MAILDIR_PATH}/${directory}/tmp -maxdepth 1 -type
f -exec sh -c "if [ -s \"\${1}\" ]; then mv -f \${1}
${MAILDIR_PATH}/${directory}/; fi" x {} \;
kill ${PIDOFMAILDIRLOCK}
echo "Compressed ${MAILDIR_PATH}/${directory}..."
# Remove dovecot index files to have no issues with
mails
find "${MAILDIR_PATH}" -type f -name dovecot.index\*
-delete
echo "Size after compression: `du -sh
\"${MAILDIR_PATH}/${directory}\" | awk '{print $1}'`"
else
echo "Failed to lock: ${MAILDIR_PATH}/${directory}" >&2
find ./tmp/ -maxdepth 1 -group mail -type f -delete
fi
fi
};
done
exit 0
--
Best regards,
Martynas Bendorius
> On 2019-12-08, at 15:21, @lbutlr via dovecot <dovecot@dovecot.org> wrote:
>
> On 08 Dec 2019, at 05:58, @lbutlr <krem...@kreme.com> wrote:
>> On 06 Dec 2019, at 16:28, Martynas Bendorius <marty...@martynas.it> wrote:
>>> when zlib compression is enabled in dovecot, old emails remain untouched
>>
>> I’ve been considering doing this, or at least looking into how much space
>> we’d save (answer so far, less than you might think), but I am hesitant to
>> “alter” the user’s mail stores without a bit more guidance.
>>
>> Has anyone found a good walkthrough/guide on setting this up and also on
>> compressing the old mail?
>>
>> Are there any common issues to watch out for? Is it entirely transparent to
>> the user?
>>
>> https://wiki2.dovecot.org/Plugins/Zlib says it has moved to
>> https://doc.dovecot.org/plugin-settings/zlib_plugin/ which does not exist.
>>
>> "Not Found
>> The requested URL /plugin-settings/zlib_plugin/ was not found on this
>> server."
>
> The ULR on that page has the _ character instead of a - in the URL.
>
> <https://doc.dovecot.org/plugin-settings/zlib-plugin/> loads and leads to
>
> <https://doc.dovecot.org/configuration_manual/zlib_plugin/#zlib-plugin>
>
> Which, sadly, does not have example code on actually compressing the existing
> mail, but does say to use maildirlock.
>
>
>
>
> --
> Wife: Who are you talking to? Husb: [on phone] Jon Wife: Aren't you
> going to talk to me? Husb: I talked to you at dinner, do I need
> to talk to you again?
