Changing the name of a compressed file
Peter West
lists at pbw.id.au
Sun Jun 11 14:46:33 EEST 2017
It looks as though there is no global mail_plugins variable. Is this the case? Or have I misunderstood how global variable are expressed?
P
> On 10 Jun 2017, at 9:10 pm, Peter West <lists at pbw.id.au> wrote:
>
> Ok, I added zlib to imap protocol.
>
> protocol imap {
> …
> mail_plugins = $mail_plugins zlib
> }
>
> Now both imap and lmtp protocols have zlib plugin enabled, and both send and receive mail is compressed.
>
> Peter
>
>> On 10 Jun 2017, at 6:50 pm, Aki Tuomi <aki.tuomi at dovecot.fi> wrote:
>>
>> Please check that you are not overwriting mail plugins for lmtp. Or post your doveconf -n.
>>
>> Aki
>>
>>> On June 10, 2017 at 11:10 AM Peter West <lists at pbw.id.au> wrote:
>>>
>>>
>>> Not sure what you mean. I’m using lmtp to send messages to Dovecot from Postfix.
>>>
>>>> On 10 Jun 2017, at 6:08 pm, Aki Tuomi <aki.tuomi at dovecot.fi> wrote:
>>>>
>>>> What's your LDA?
>>>>
>>>> Aki
>>>>
>>>>> On June 10, 2017 at 11:01 AM Peter West <lists at pbw.id.au> wrote:
>>>>>
>>>>>
>>>>> Thanks for that Aki.
>>>>>
>>>>> Follow-up question. I tried to initiate compression by adding
>>>>>
>>>>> mail_plugins = $mail_plugins zlib
>>>>>
>>>>> plugin {
>>>>> zlib_save_level = 6
>>>>> zlib_save = xz
>>>>> }
>>>>>
>>>>>
>>>>> to dovecot.conf. I restarted dovecot and sent one message to the server, and one message from the server. Neither was compressed. I changed the save type to
>>>>>
>>>>> zlib_save = bz2
>>>>>
>>>>> and repeated. This time the message received (in /var/vmail/<host>/<username>/cur) was not compressed, but the message in /var/vmail/<host>/<username>/.Sent/cur was bzip2 compressed.
>>>>>
>>>>> Why is the received mail not being compressed? Is this the point of the discussion about compressing old mails?
>>>>>
>>>>>
>>>>>> On 10 Jun 2017, at 4:43 pm, Aki Tuomi <aki.tuomi at dovecot.fi> wrote:
>>>>>>
>>>>>>
>>>>>>> On June 10, 2017 at 5:58 AM Peter West <lists at pbw.id.au> wrote:
>>>>>>>
>>>>>>>
>>>>>>> Concerning Maildir, the wiki page on compression has this:
>>>>>>>
>>>>>>> All mails must have ,S=<size> in their filename where <size> contains the original uncompressed mail size, otherwise there will be problems with quota calculation as well as other potential random failures. 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.
>>>>>>>
>>>>>>> Further down on the same page is this:
>>>>>>>
>>>>>>> If the file does exist, rename() (mv) the compressed file over the original file.
>>>>>>> • Dovecot can now read the file, but to avoid compressing it again on the next run, you'll probably want to rename it again to include e.g. a "Z" flag in the file name to mark that it was compressed (e.g. 1223212411.M907959P17184.host,S=3271:2,SZ).
>>>>>>>
>>>>>>> These comments seem to contradict each. Or is there a difference between adding the size specifier to the filename and adding a Z flag to the end of the file name?
>>>>>>>
>>>>>>> --
>>>>>>> Peter West
>>>>>>> pbw at pbw.id.au
>>>>>>> And the great throng heard him gladly.
>>>>>>>
>>>>>>
>>>>>> Keyword is 'base filename'. From the wiki, "The standard filename definition is: "<base filename>:2,<flags>".". Z is a flag.
>>>>>>
>>>>>> Aki
>>>>>
>>>
>
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