overview zlib efficiency? Summary and added note

[Harald Leithner]

Hi,

use "doveadm" to get all real message

doveadm -f table fetch -A "size.physical" ALL | awk 
'{s+=$2}END{printf("%.2fMB\n", s/1024/1024);}'

189247.67MB .. 185G

use "du" to get size on disc:

In my case
with deduplication:

/srv/stroage/# du -s -h *
53G     vmail
75G     vmail_sis

without deduplication

/srv/stroage/# du -s -h -l *
53G     vmail
209G    vmail_sis

j4i, SIS can't use the zlib plugin so the 75G in my case are not 
compressed (I haven't a filesystem that I trust and has a compression 
feature). Anyway it has a 3:1 ratio in my case.

Maybe I interpret the SIS wrong and SIS couldn't be counted with du -l 
(count links).

But if someone doesn't have SIS this values should be point you into the 
right direction.

bye

Harald

Am 16.03.2016 um 08:50 schrieb Götz Reinicke - IT Koordinator:
> Am 15.03.16 um 16:01 schrieb Götz Reinicke - IT Koordinator:
>> Hi,
>>
>> may be someone has already done that: Do you have a script(?) tool which
>> shows the efficiency of the mail compression if zlib is used?
>>
>> Something that shows the uncompressed size vrs. the compressed.
>
> Hi,
>
> maybe my question was a bit misleading. But anyway thanks for your
> feedback regarding your experiences and compression rates.
>
> We already thought about the benefit of less IO and more CPU power,
> which is no concern.
>
> The mailboxes I checked also go with 40-60% compression rate.
>
> But what I was looking for was a tool or way to see what volume would be
> used if we where not using compression.
>
> e.g. "du -hs --without-zlib"
>
> Our management would like to see a graph one day which shows the volume
> uncompressed and compressed ...
>
> Adding zlib with mdbox or maildir - as we do it currently - is from my
> POV if you have the CPU power a MUST :)
>
> 	happy dovecoting - Götz
>
>
>

-- 
Harald Leithner

ITronic
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