[postfix-jp:02670] kernel Out of Memory？

[Masanori Tamashiro <tamax@xxxxxxxxxxxxxx>]

はじめまして玉城と申します。

postfix-1.1.7を導入/サーバ運用し始めて１年経過したのですが、
先週突然サーバがダウンしました。シングルユーザモードで
起動し直してログを見た所、以下のようなwarningが・・
（※ smtpの処理後に発生しているようです。正常終了が出来ていないのかな？）
再起動後、wnn7とcannaを切って稼動できたので（正常に起動しなかったので）
暫定運用しております。
何が直接の原因なのか掴めず困っております。どなたか良い知恵をお貸し下さい。

<<System：Vinelinux2.5CR postfix/cyrus-sasl(smtp_auth)/qpopper(apop)>>
[maillog]------------------------------------------------------
Apr  2 17:38:04 mail1 postfix/smtp[1868]: 6E1F036C019: to=<abcd@xxxxxxxxx>,relay=abcd@xxxxxxxxx[***.***.***.67], delay=5, status=sent (250 2.0.0
h328fxp05713 Message accepted for delivery)
Apr  2 17:38:09 mail1 postfix/master[1053]: warning: process /usr/libexec/postfix/smtpd pid 1867 killed by signal 9
Apr  2 17:38:23 mail1 postfix/master[1053]: warning: process /usr/libexec/postfix/smtp pid 1868 killed by signal 9
Apr  2 17:38:46 mail1 in.qpopper[1869]: apop "cccc"
Apr  2 17:38:51 mail1 postfix/smtpd[1870]: connect from ***.***.*****.co.jp[***.***.***.101]
Apr  2 17:38:51 mail1 postfix/smtpd[1870]: A734D36C019: client=***.***.co.jp[***.***.***.101]
Apr  2 17:38:52 mail1 postfix/cleanup[1840]: A734D36C019: message-id=<*****@****.****.****.co.jp>
Apr  2 17:38:52 mail1 postfix/master[1053]: warning: process /usr/libexec/postfix/smtpd pid 1870 killed by signal 9
Apr  2 17:38:52 mail1 postfix/master[1053]: warning: /usr/libexec/postfix/smtpd: bad command startup -- throttling
Apr  2 17:38:52 mail1 postfix/cleanup[1840]: warning: unknown_stream: unexpected EOF in data, record type 78 length 76
Apr  2 17:39:04 mail1 postfix/master[1053]: warning: process /usr/libexec/postfix/cleanup pid 1840 killed by signal 9
Apr  2 17:39:05 mail1 in.qpopper[1871]: apop "dddd"
Apr  2 17:39:06 mail1 in.qpopper[1871]: Stats: dddd 0 0 0 0 ****.****.NE.JP ***.***.***.105
Apr  2 17:39:06 mail1 in.qpopper[1869]: Stats: cccc 2 143786 0 0 ****.****.NE.JP ***.***.***.105
Apr  2 17:39:55 mail1 postfix/master[1053]: warning: process /usr/libexec/postfix/trivial-rewrite pid 1815 killed by signal 9
Apr  2 17:39:55 mail1 postfix/master[1053]: warning: /usr/libexec/postfix/trivial-rewrite: bad command startup -- throttling
Apr  2 17:40:52 mail1 postfix/smtpd[1872]: connect from ***.*****.ne.jp[***.***.***.206]
Apr  2 17:40:52 mail1 postfix/smtpd[1872]: 6B1A336C019: client=***.*****.ne.jp[***.***.***.206]
Apr  2 17:40:53 mail1 postfix/master[1053]: warning: process /usr/libexec/postfix/smtpd pid 1872 killed by signal 9
Apr  2 17:40:53 mail1 postfix/master[1053]: warning: /usr/libexec/postfix/smtpd: bad command startup -- throttling
Apr  2 17:40:53 mail1 postfix/cleanup[1873]: warning: end of input while receiving integer data from service unknown_stream
Apr  2 17:40:55 mail1 postfix/trivial-rewrite[1874]: warning: write rewrite reply: Broken pipe
Apr  2 17:41:05 mail1 postfix/master[1053]: warning: process /usr/libexec/postfix/cleanup pid 1873 killed by signal 9
Apr  2 17:41:17 mail1 postfix/master[1053]: warning: process /usr/libexec/postfix/trivial-rewrite pid 1874 killed by signal 9
Apr  2 17:41:17 mail1 postfix/master[1053]: warning: /usr/libexec/postfix/trivial-rewrite: bad command startup -- throttling
Apr  2 17:43:20 mail1 in.qpopper[1875]: apop "aaaaa"

さらに、message の方にも、

[message]------------------------------------------------------
Mar 30 04:02:01 mail1 syslogd 1.4-0: restart.
Apr  2 17:36:12 mail1 kernel: Out of Memory: Killed process 1839 (smtpd).
Apr  2 17:37:06 mail1 kernel: Out of Memory: Killed process 1862 (smtpd).
Apr  2 17:37:29 mail1 kernel: Out of Memory: Killed process 1866 (smtpd).
Apr  2 17:38:09 mail1 kernel: Out of Memory: Killed process 1867 (smtpd).
Apr  2 17:38:23 mail1 kernel: Out of Memory: Killed process 1868 (smtp).
Apr  2 17:38:52 mail1 kernel: Out of Memory: Killed process 1870 (smtpd).
Apr  2 17:39:04 mail1 kernel: Out of Memory: Killed process 1840 (cleanup).
Apr  2 17:39:55 mail1 kernel: Out of Memory: Killed process 1815 (trivial-rewrite).
Apr  2 17:40:19 mail1 kernel: Out of Memory: Killed process 582 (identd).
Apr  2 17:40:19 mail1 kernel: Out of Memory: Killed process 585 (identd).
Apr  2 17:40:19 mail1 kernel: Out of Memory: Killed process 588 (identd).
Apr  2 17:40:19 mail1 kernel: Out of Memory: Killed process 589 (identd).
Apr  2 17:40:19 mail1 kernel: Out of Memory: Killed process 590 (identd).
Apr  2 17:40:53 mail1 kernel: Out of Memory: Killed process 1872 (smtpd).
Apr  2 17:41:05 mail1 kernel: Out of Memory: Killed process 1873 (cleanup).
Apr  2 17:41:17 mail1 kernel: Out of Memory: Killed process 1874 (trivial-rewrite).
Apr  2 17:42:18 mail1 kernel: Out of Memory: Killed process 726 (xfs).
Apr  2 17:44:05 mail1 kernel: Out of Memory: Killed process 1894 (smtpd).
Apr  2 17:48:37 mail1 kernel: Out of Memory: Killed process 1920 (smtpd).
Apr  2 17:49:10 mail1 kernel: Out of Memory: Killed process 1923 (smtpd).
Apr  2 17:49:22 mail1 kernel: Out of Memory: Killed process 1921 (cleanup).
Apr  2 17:49:46 mail1 kernel: Out of Memory: Killed process 1896 (trivial-rewrite).
Apr  2 17:50:13 mail1 kernel: Out of Memory: Killed process 1922 (local).
Apr  2 17:50:49 mail1 kernel: Out of Memory: Killed process 1718 (pickup).
Apr  2 17:51:04 mail1 kernel: Out of Memory: Killed process 1927 (pickup).
Apr  2 17:51:18 mail1 kernel: Out of Memory: Killed process 637 (jserver).
Apr  2 17:52:32 mail1 kernel: Out of Memory: Killed process 1929 (jserver).
Apr  2 17:53:05 mail1 kernel: Out of Memory: Killed process 1936 (smtpd).
Apr  2 17:53:11 mail1 kernel: Out of Memory: Killed process 1934 (jserver).
Apr  2 17:53:53 mail1 kernel: Out of Memory: Killed process 1950 (jserver).
Apr  2 17:54:06 mail1 kernel: Out of Memory: Killed process 1961 (jserver).
Apr  2 17:58:23 mail1 kernel: Out of Memory: Killed process 1962 (jserver).
Apr  2 17:58:35 mail1 kernel: Out of Memory: Killed process 1969 (jserver).
Apr  2 17:58:48 mail1 kernel: Out of Memory: Killed process 1971 (jserver).
Apr  2 18:01:12 mail1 kernel: Out of Memory: Killed process 1972 (jserver).
Apr  2 18:01:20 mail1 kernel: Out of Memory: Killed process 1976 (jserver).
Apr  2 18:01:21 mail1 kernel: VM: killing process jserver

==================================
 中沼アートスクリーン株式会社
 技術グループ
 Masanori Tamashiro　　 玉城　正規
  e-mail : tamax@xxxxxxxxxxxxxx
==================================