mdbox + zlib performing less than just mdbox

[Marc Roos]

I have test environment to determine what would be best settings. I have 
been told that enabling zlib compression would be good to save iops on 
storage. But doing the test now, I get worse results. 

[@test2 ~]# pr -m -t mail04-mdbox-vdb-append-64kb-6.log 
mail04-mdbox-vdb-append-64kb-8.log |less
Logi Sele Appe                      Logi Sele Appe
100% 100% 100%                      100% 100% 100%
   1    1    6   1/  1                 1    1    6   1/  1
   0    0    9   1/  1                 0    0    8   1/  1
   0    0    7   1/  1                 0    0    8   1/  1
   0    0   10   1/  1                 0    0    9   1/  1
   0    0    7   1/  1                 0    0    6   1/  1
   0    0    8   1/  1                 0    0    8   1/  1
   0    0    9   1/  1                 0    0    8   1/  1
   0    0   10   1/  1                 0    0    8   1/  1
   0    0    9   1/  1                 0    0    7   1/  1
   0    0   11   1/  1                 0    0    7   1/  1
  29    3 1093 ms/cmd avg             43    2 1232 ms/cmd avg
Logi Sele Appe                      Logi Sele Appe
100% 100% 100%                      100% 100% 100%
   0    0   10   1/  1                 0    0    9   1/  1
   0    0    9   1/  1                 0    0    7   1/  1
   0    0   10   1/  1                 0    0    7   1/  1
   0    0    9   1/  1                 0    0    6   1/  1
   0    0   11   1/  1                 0    0    8   1/  1
   0    0    9   1/  1                 0    0    7   1/  1
   0    0    8   1/  1                 0    0    6   1/  1
   0    0   11   1/  1                 0    0    7   1/  1
   0    0    9   1/  1                 0    0    5   1/  1
   0    0    9   1/  1                 0    0    9   1/  1
   0    0 1063 ms/cmd avg              0    0 1413 ms/cmd avg
Logi Sele Appe                      Logi Sele Appe
100% 100% 100%                      100% 100% 100%
   0    0    8   1/  1                 0    0    8   1/  1
   0    0   10   1/  1                 0    0    8   1/  1
   0    0    7   1/  1                 0    0    8   1/  1
   0    0   10   1/  1                 0    0    6   1/  1
   0    0   10   1/  1                 0    0    7   1/  1
   0    0   11   1/  1                 0    0    8   1/  1
   0    0    7   1/  1                 0    0    8   1/  1
   0    0   11   1/  1                 0    0    6   1/  1
   0    0    8   1/  1                 0    0    7   1/  1
   0    0   10   1/  1                 0    0    8   1/  1
   0    0 1077 ms/cmd avg              0    0 1382 ms/cmd avg
Logi Sele Appe                      Logi Sele Appe
100% 100% 100%                      100% 100% 100%
   0    0    7   1/  1                 0    0    6   1/  1
   0    0    9   1/  1                 0    0    4   1/  1
   0    0    6   1/  1                 0    0    7   1/  1
   0    0    9   1/  1                 0    0    7   1/  1
   0    0    8   1/  1                 0    0    7   1/  1
   0    0   10   1/  1                 0    0    5   1/  1
   0    0    9   1/  1                 0    0    8   1/  1
   0    0    7   1/  1                 0    0    6   1/  1
   0    0    9   1/  1                 0    0    6   1/  1
   0    0    7   1/  1                 0    0    8   1/  1
   0    0 1246 ms/cmd avg              0    0 1524 ms/cmd avg
...
...
...
Logi Sele Appe                      Logi Sele Appe
100% 100% 100%                      100% 100% 100%
   0    0    8   1/  1                 0    0    5   1/  1
   0    0    6   1/  1                 0    0    4   1/  1
   0    0    6   1/  1                 0    0    4   1/  1
   0    0    7   1/  1                 0    0    4   1/  1
   0    0    5   1/  1                 0    0    5   1/  1
   0    0    5   1/  1                 0    0    4   1/  1
   0    0    6   1/  1                 0    0    4   1/  1
   0    0    7   1/  1                 0    0    5   1/  1
   0    0    6   1/  1                 0    0    4   1/  1
   0    0    7   1/  1                 0    0    5   1/  1
   0    0 1596 ms/cmd avg              0    0 2308 ms/cmd avg
Logi Sele Appe                      Logi Sele Appe
100% 100% 100%                      100% 100% 100%
   0    0    7   1/  1                 0    0    4   1/  1
   0    0 1583 ms/cmd avg              0    0    4   1/  1
                                       0    0 2331 ms/cmd avg
Totals:
Logi Sele Appe                      Totals:
100% 100% 100%                      Logi Sele Appe
   1    1 1978                      100% 100% 100%
                                       1    1 1145