[Dovecot] mdbox-files over 2 MB

Jesus Cea jcea at jcea.es
Wed Oct 1 13:43:18 UTC 2014


I keep the quoted message complete because the original thread was
posted six months ago. I am top-posting, no comments inside the quoted text.

I plan to write a blog about mdbox oddities but in the meantime I can
tell you that if you store attachments "detached" in your mdbox storage
the issue is this:

1. You have a 200Kbytes MB m.* file you are currently targeting.

2. You have a new email to store. Lets say it has a 3MB attachment.

3. You have a 2MB mdbox max file size .

4. Dovecot notices that 0.2+3 > 2, so it will create a new m.* file.

5. When storing the message, it will store the attachment outside of the
mbox, so the new m.* file will be, lets say, 5Kbytes only.

6. Now you have 2 m.* files: one of 200 Kbytes and other of 5Kbytes.

7. Dovecot tries to reuse undersized m.* files, but it is quite
forgiving. I have some private patches to increase its agressiveness.

If you don't detach attachment, you probably have the same issue: when a
new message makes a m.* file to oversize, dovecot creates a new m.* file
and leave the old one alone, so it will be undersized.



On 06/05/14 03:05, Stan Hoeppner wrote:
> On 5/5/2014 2:23 PM, Patrick Domack wrote:
>> Quoting Reindl Harald <h.reindl at thelounge.net>:
>>
>>> Am 05.05.2014 16:10, schrieb Hardy Flor:
>>>> Is there really no one with this problem?
>>>
>>> next time quote the problem instead demand
>>> others to seek for you in the archives
>>
>> Even searching for him in the archives, I have no idea what he thinks is
>> a problem.
>>
>> I know I have no issues using mdbox, with 2mb or 50mb rotate sizes.
> 
> 
> He's wondering why many of his mdbox files are much smaller than 2 MB.
> His original post:
> 
> 
> On 3/17/2014 1:29 AM, Hardy Flor wrote:
>> Hello,
>>
>> there are copies with different size in 3 mailboxes of the user
>> sequentially about 3800 emails.
>> why not something 2MB files?
>>
>> After the big file "m.00000034" with 14MB follow very many small ...
>>
>> ------------------------------------- doveconf:
>>
>> # 2.2.12: /etc/dovecot/dovecot.conf
>> # OS: Linux 3.2.0-4-amd64 x86_64 Debian 7.4 ext4
>> mail_attachment_dir = /var/mail/attachments
>> mail_attachment_hash = %{md5}
>> mail_attachment_min_size = 16 k
>> mail_location = mdbox:/var/mail/user/%n
>> mdbox_rotate_interval = 1 weeks
>> mdbox_rotate_size = 2 M
>>
>> ------------------------------------- directory:
>>
>> root at xxx:/var/mail/user/xxx/storage# ls -al
>> insgesamt 76532
>> drwx--S--- 2 vmail mail     4096 Mär 16 13:52 .
>> drwx--S--- 6 vmail mail     4096 Mär 16 12:10 ..
>> -rw------- 1 vmail mail    74360 Mär 16 12:39 dovecot.map.index
>> -rw------- 1 vmail mail    25204 Mär 16 13:52 dovecot.map.index.log
>> -rw------- 1 vmail mail    63544 Mär 16 12:39 dovecot.map.index.log.2
>> -rw------- 1 vmail mail  2092921 Mär 16 12:15 m.00000001
>> -rw------- 1 vmail mail  2086746 Mär 16 12:15 m.00000002
>> -rw------- 1 vmail mail  2084182 Mär 16 12:15 m.00000003
>> -rw------- 1 vmail mail  2096826 Mär 16 12:15 m.00000004
>> -rw------- 1 vmail mail  1882666 Mär 16 12:15 m.00000005
>> -rw------- 1 vmail mail  1903965 Mär 16 12:15 m.00000006
>> -rw------- 1 vmail mail  2091169 Mär 16 12:15 m.00000007
>> -rw------- 1 vmail mail  2086396 Mär 16 12:15 m.00000008
>> -rw------- 1 vmail mail   507205 Mär 16 12:16 m.00000009
>> -rw------- 1 vmail mail  2031456 Mär 16 12:17 m.00000010
>> -rw------- 1 vmail mail  2095697 Mär 16 12:17 m.00000011
>> -rw------- 1 vmail mail  1689071 Mär 16 12:17 m.00000012
>> -rw------- 1 vmail mail  2092124 Mär 16 12:17 m.00000013
>> -rw------- 1 vmail mail  1950602 Mär 16 12:17 m.00000014
>> -rw------- 1 vmail mail  2092215 Mär 16 12:17 m.00000015
>> -rw------- 1 vmail mail  2087463 Mär 16 12:17 m.00000016
>> -rw------- 1 vmail mail  2079795 Mär 16 12:17 m.00000017
>> -rw------- 1 vmail mail  2014121 Mär 16 12:17 m.00000018
>> -rw------- 1 vmail mail  2081893 Mär 16 12:17 m.00000019
>> -rw------- 1 vmail mail  2092088 Mär 16 12:17 m.00000020
>> -rw------- 1 vmail mail  2090508 Mär 16 12:17 m.00000021
>> -rw------- 1 vmail mail  1929296 Mär 16 12:17 m.00000022
>> -rw------- 1 vmail mail  2067685 Mär 16 12:17 m.00000023
>> -rw------- 1 vmail mail  1745743 Mär 16 12:20 m.00000024
>> -rw------- 1 vmail mail   866452 Mär 16 12:20 m.00000025
>> -rw------- 1 vmail mail   296379 Mär 16 12:20 m.00000026
>> -rw------- 1 vmail mail   433541 Mär 16 12:39 m.00000027
>> -rw------- 1 vmail mail    92526 Mär 16 12:39 m.00000028
>> -rw------- 1 vmail mail    19094 Mär 16 12:39 m.00000029
>> -rw------- 1 vmail mail   106837 Mär 16 12:39 m.00000030
>> -rw------- 1 vmail mail   162012 Mär 16 12:39 m.00000031
>> -rw------- 1 vmail mail   412080 Mär 16 13:51 m.00000032
>> -rw------- 1 vmail mail  1715868 Mär 16 13:51 m.00000033
>> -rw------- 1 vmail mail 14433784 Mär 16 13:51 m.00000034
>> -rw------- 1 vmail mail     3280 Mär 16 13:51 m.00000035
>> -rw------- 1 vmail mail     6308 Mär 16 13:51 m.00000036
>> -rw------- 1 vmail mail   534274 Mär 16 13:51 m.00000037
>> -rw------- 1 vmail mail   378719 Mär 16 13:51 m.00000038
>> -rw------- 1 vmail mail   458528 Mär 16 13:51 m.00000039
>> -rw------- 1 vmail mail   192504 Mär 16 13:51 m.00000040
>> -rw------- 1 vmail mail  1277766 Mär 16 13:51 m.00000041
>> -rw------- 1 vmail mail    33417 Mär 16 13:51 m.00000042
>> -rw------- 1 vmail mail   142866 Mär 16 13:51 m.00000043
>> -rw------- 1 vmail mail   113529 Mär 16 13:51 m.00000044
>> -rw------- 1 vmail mail    55888 Mär 16 13:51 m.00000045
>> -rw------- 1 vmail mail   673504 Mär 16 13:51 m.00000046
>> -rw------- 1 vmail mail   430738 Mär 16 13:51 m.00000047
>> -rw------- 1 vmail mail   218494 Mär 16 13:51 m.00000048
>> -rw------- 1 vmail mail    96165 Mär 16 13:51 m.00000049
>> -rw------- 1 vmail mail     8370 Mär 16 13:51 m.00000050
>> -rw------- 1 vmail mail    29251 Mär 16 13:51 m.00000051
>> -rw------- 1 vmail mail   394680 Mär 16 13:51 m.00000052
>> -rw------- 1 vmail mail   674892 Mär 16 13:51 m.00000053
>> -rw------- 1 vmail mail  1076919 Mär 16 13:51 m.00000054
>> -rw------- 1 vmail mail   258806 Mär 16 13:51 m.00000055
>> -rw------- 1 vmail mail    60069 Mär 16 13:51 m.00000056
>> -rw------- 1 vmail mail   297891 Mär 16 13:51 m.00000057
>> -rw------- 1 vmail mail    92772 Mär 16 13:51 m.00000058
>> -rw------- 1 vmail mail   129272 Mär 16 13:51 m.00000059
>> -rw------- 1 vmail mail    56073 Mär 16 13:51 m.00000060
>> -rw------- 1 vmail mail   528260 Mär 16 13:51 m.00000061
>> -rw------- 1 vmail mail    29468 Mär 16 13:51 m.00000062
>> -rw------- 1 vmail mail     3250 Mär 16 13:51 m.00000063
>> -rw------- 1 vmail mail    96445 Mär 16 13:51 m.00000064
>> -rw------- 1 vmail mail   337663 Mär 16 13:51 m.00000065
>> -rw------- 1 vmail mail   187505 Mär 16 13:51 m.00000066
>> -rw------- 1 vmail mail    98839 Mär 16 13:51 m.00000067
>> -rw------- 1 vmail mail     5294 Mär 16 13:51 m.00000068
>> -rw------- 1 vmail mail    28276 Mär 16 13:51 m.00000069
>> -rw------- 1 vmail mail    67950 Mär 16 13:52 m.00000070
>> -rw------- 1 vmail mail   704457 Mär 16 13:52 m.00000071
>> -rw------- 1 vmail mail  1410205 Mär 16 13:52 m.00000072
>> -rw------- 1 vmail mail   736330 Mär 16 13:52 m.00000073
>> -rw------- 1 vmail mail   616992 Mär 16 13:52 m.00000074
> 

-- 
Jesús Cea Avión                         _/_/      _/_/_/        _/_/_/
jcea at jcea.es - http://www.jcea.es/     _/_/    _/_/  _/_/    _/_/  _/_/
Twitter: @jcea                        _/_/    _/_/          _/_/_/_/_/
jabber / xmpp:jcea at jabber.org  _/_/  _/_/    _/_/          _/_/  _/_/
"Things are not so easy"      _/_/  _/_/    _/_/  _/_/    _/_/  _/_/
"My name is Dump, Core Dump"   _/_/_/        _/_/_/      _/_/  _/_/
"El amor es poner tu felicidad en la felicidad de otro" - Leibniz

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