overview zlib efficiency?

[Rick Romero]

  Quoting Rick Romero <rick at havokmon.com>:

> Quoting Robert L Mathews <lists at tigertech.com>:
>
>> On 3/15/16 10:13 AM, Sven Hartge wrote:
>>
>>> I don't have a script, but I can provide some numbers. I did a test
with
>>> a server for about 10.000 users and 2TB worth of mail, converting from
>>> Maildir++ to mdbox with zlib (level = 6) and had a final size of 1TB,
so
>>> 2:1 reduction.
>>
>> These numbers roughly match my results. About 6 TB of mail compresses
>> down to about 3 TB.
>>
>> Also keep in mind that even if it does increase CPU usage, it reduces
>> disk usage. This is probably an excellent tradeoff for most people,
>> since most servers are limited by disk throughput/latency more than CPU
>> power.
>
> Just thought I'd add, because it frustrated me and it's an amusing
> anecdote
> to this - The new 4k ashift doubled my disk usage of Maildir++ mail.
>
> So logically, if you're migrating from maildir++ to mdbox on 4k sector
> system, you may see a sizable decrease in disk usage without a
compression
> change.
> Rick

With ZFS - Sorry - I dropped that in my edit.