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bartu
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Hi,
i've been expiriencing lately major problem with qmail speed on centralized mail server. It accepts incoming emails (you have to wait a long time for it) and places them in the queue. Problem is, that email are delivered to loacal recipients so slowly that queue keeps growing bigger. I haven't noticed such problem for outgoing emails.
Form observing top and vmastat i assumed that it's related to HDD work.
************
here's lsof output:
root@cmail:~# lsof |wc -l
3579
root@cmail:~# lsof |grep qmail|wc -l
586
************
and vmstat output:
root@cmail:~# vmstat 1 10
procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
0 6 0 930480 99480 738756 0 0 368 155 119 136 3 1 74 22
0 6 0 930236 99488 738884 0 0 132 248 211 128 0 0 75 25
0 5 0 929440 99500 739144 0 0 260 468 305 469 2 0 75 23
0 4 0 929320 99504 739276 0 0 136 468 241 114 0 0 75 25
1 4 0 928892 99512 739404 0 0 124 348 232 275 1 0 72 27
0 2 0 928512 99520 739396 0 0 32 608 203 166 0 0 75 25
0 4 0 926696 99536 739788 0 0 176 336 359 486 7 1 68 24
2 2 0 924724 99576 740632 0 0 600 900 377 603 22 1 49 28
0 3 0 923584 99592 740616 0 0 12 516 203 492 8 2 50 39
0 4 0 922872 99592 740616 0 0 32 592 226 192 2 0 65 32
************
I've also made a test that showed that qmail is responsible for this
root@cmail:~# hdparm -t /dev/sda
/dev/sda:
Timing buffered disk reads: 20 MB in 3.32 seconds = 6.02 MB/sec
root@cmail:~# /etc/init.d/qmail stop
root@cmail:~# /etc/init.d/xinetd stop
Stopping internet superserver: xinetd.
root@cmail:~# killall -9 qmail-smtpd
root@cmail:~# hdparm -t /dev/sda
/dev/sda:
Timing buffered disk reads: 366 MB in 3.00 seconds = 122.00 MB/sec
************
I can add that CPU is used mosly on processess like: syslog, spamd, mysql, qmail processes
i've been expiriencing lately major problem with qmail speed on centralized mail server. It accepts incoming emails (you have to wait a long time for it) and places them in the queue. Problem is, that email are delivered to loacal recipients so slowly that queue keeps growing bigger. I haven't noticed such problem for outgoing emails.
Form observing top and vmastat i assumed that it's related to HDD work.
************
here's lsof output:
root@cmail:~# lsof |wc -l
3579
root@cmail:~# lsof |grep qmail|wc -l
586
************
and vmstat output:
root@cmail:~# vmstat 1 10
procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
0 6 0 930480 99480 738756 0 0 368 155 119 136 3 1 74 22
0 6 0 930236 99488 738884 0 0 132 248 211 128 0 0 75 25
0 5 0 929440 99500 739144 0 0 260 468 305 469 2 0 75 23
0 4 0 929320 99504 739276 0 0 136 468 241 114 0 0 75 25
1 4 0 928892 99512 739404 0 0 124 348 232 275 1 0 72 27
0 2 0 928512 99520 739396 0 0 32 608 203 166 0 0 75 25
0 4 0 926696 99536 739788 0 0 176 336 359 486 7 1 68 24
2 2 0 924724 99576 740632 0 0 600 900 377 603 22 1 49 28
0 3 0 923584 99592 740616 0 0 12 516 203 492 8 2 50 39
0 4 0 922872 99592 740616 0 0 32 592 226 192 2 0 65 32
************
I've also made a test that showed that qmail is responsible for this
root@cmail:~# hdparm -t /dev/sda
/dev/sda:
Timing buffered disk reads: 20 MB in 3.32 seconds = 6.02 MB/sec
root@cmail:~# /etc/init.d/qmail stop
root@cmail:~# /etc/init.d/xinetd stop
Stopping internet superserver: xinetd.
root@cmail:~# killall -9 qmail-smtpd
root@cmail:~# hdparm -t /dev/sda
/dev/sda:
Timing buffered disk reads: 366 MB in 3.00 seconds = 122.00 MB/sec
************
I can add that CPU is used mosly on processess like: syslog, spamd, mysql, qmail processes
