[dovecot] current cvs

[Farkas Levente]

hi,
so after upgrade to the current cvs all of our problem disappear:-)
but we don't have time to test the ssl part...
although after I compile and install the new dovecot I stop it I do a
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find /home/*/Maildir -name '.imap*' -exec rm {} \;
find /home/*/Maildir -name 'dovecot-uidlist' -exec rm {} \;
find /home/*/Maildir -name 'msgid.cache' -exec rm {} \;
find /home/*/Maildir -name '.customflags' -exec rm {}\;
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just to be sure that we use a fresh version and no other problem can be 
caused by the old index or any other cached files.
this was a BIG mistake!!!
we've got about 300 users and about 100 online at the same time. after a 
two minutes break (while I reinstall and delete) every user check his 
mail which casue a load about 90!!! the cpu usage 1-2% but the avarage 
load was 90 (curently about 0.22)! the reason was IO. we have to stop 
imap and wait for a while...
I don't know the exact reason bu I assume dovecot is regenerate 
everybody's index a other cache at the same time. is there any way to 
reduce the possible number of IO load? this would be useful if never 
happend again!:-)

this happend around 4:40.
the output of sar -b:
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03:00:00 PM       tps      rtps      wtps   bread/s   bwrtn/s
03:10:00 PM     48.18     29.19     18.99   1456.53    771.29
03:20:00 PM     41.66     25.80     15.86   1054.88    830.05
03:30:00 PM     42.64     25.67     16.97   1223.03    759.77
03:40:00 PM     44.98     31.95     13.03   1959.15    467.40
03:50:00 PM     26.68     14.63     12.05    741.48    424.12
04:00:00 PM     25.80     11.70     14.10    516.21    450.04
04:10:00 PM     59.55     34.91     24.64   1755.07    939.11
04:20:00 PM     95.98     61.15     34.83   4453.24   1563.25
04:30:00 PM     95.08     55.45     39.63   2182.22   1591.56
04:40:00 PM    168.85    145.99     22.86  11155.73   1037.25
04:50:00 PM    135.98    106.50     29.48   7908.21   1604.76
05:00:00 PM    125.87     97.65     28.23   5876.03   1060.50
05:10:00 PM     80.83     62.92     17.90   4321.82    590.19
05:20:00 PM    102.04     77.65     24.40   4907.27   1076.92
05:30:00 PM    129.04    106.58     22.46   6387.18    883.13
05:40:00 PM     89.44     73.20     16.24   4905.64    782.94
05:50:00 PM     88.23     73.16     15.06   5539.93    965.34
06:00:00 PM     92.49     72.67     19.81   5486.25    692.18
06:10:00 PM     45.24     32.82     12.42   1711.35    618.31
06:20:00 PM     42.17     28.16     14.01    960.11    622.33
06:30:00 PM     29.90     20.24      9.66   1538.27    376.17
06:40:00 PM     25.89     12.14     13.74    796.73    833.25
06:50:00 PM     20.50      4.98     15.52    264.91    993.62
07:00:00 PM     15.08      7.57      7.52    453.41    282.63
--------------------
the output of sar -d
--------------------
04:10:00 PM   dev22-3      0.00      0.00
04:10:00 PM   dev33-0      1.76    109.55
04:10:00 PM   dev34-0      8.51    919.94
04:20:00 PM    dev3-0      8.56    183.93
04:20:00 PM   dev22-2     67.62   3798.02
04:20:00 PM   dev22-3      0.00      0.00
04:20:00 PM   dev33-0      4.80    463.81
04:20:00 PM   dev34-0     15.01   1570.73
04:30:00 PM    dev3-0      4.40    126.63
04:30:00 PM   dev22-2     77.02   2440.08
04:30:00 PM   dev22-3      0.00      0.00
04:30:00 PM   dev33-0      1.94    124.80
04:30:00 PM   dev34-0     11.73   1082.28
04:40:00 PM    dev3-0      4.78    124.56
04:40:00 PM   dev22-2    137.27  10306.18
04:40:00 PM   dev22-3      0.00      0.00
04:40:00 PM   dev33-0     13.50    410.44
04:40:00 PM   dev34-0     13.29   1351.80
04:50:00 PM    dev3-0      6.33    194.27
04:50:00 PM   dev22-2    111.50   7961.44
04:50:00 PM   dev22-3      0.00      0.00
04:50:00 PM   dev33-0      5.64    156.51
--------------------

-- 
   Levente                               "Si vis pacem para bellum!"