Problem on dcc 1.3.30 - Continue Not Asking DCC...

Gary Mills mills@cc.umanitoba.ca
Fri Mar 10 19:28:03 UTC 2006


The same thing happened again today.  It started like this:

	Mar 10 03:49:04 electra dccd[4603]: [ID 287260 mail.notice] database cleaning begun
	Mar 10 03:53:32 electra dccm[4639]: [ID 702911 mail.error] no DCC answer from electra.cc.umanitoba.ca (130.179.16.23,6277) after 7418 ms

and ended like this:

	Mar 10 03:53:40 electra dccm[4639]: [ID 702911 mail.error] continue not asking DCC 2043 seconds after failure
	Mar 10 03:53:41 electra dccd[4603]: [ID 308828 mail.notice] 1.3.30 database /usr/local/dcc/dcc_db reopened with 2037 MByte window
	Mar 10 03:53:43 electra dccm[4639]: [ID 702911 mail.error] fcntl(F_SETLKW F_WRLCK resolve lock /usr/local/dcc/map 3): Deadlock situation detected/avoided

I'm wondering if this happens whenever the RTT recalculation happens to
fall within the five minutes when the database is being cleaned?

I also did some playing with `cdcc info' and `cdcc rtt' in the morning
to see if I could adjust the recalculation time.  Notice how the RTT
values are very high for the local database, but they go down to
practically nothing when the switch occurs...

  # cdcc info
  # 03/10/06 09:19:05 CST  /usr/local/dcc/map
  # Re-resolve names after 09:53:41
  # 2726.39 ms threshold, 2856.72 ms average    2 total, 2 working servers
  IPv6 off
  
  electra.cc.umanitoba.ca,-    RTT+0 ms    32769 XXXXXX
  #  130.179.16.23,-                                              UofM ID 1032
  #      16% of 32 requests ok 2626.39+0 ms RTT            0 ms queue wait
  
  zaurak.cc.umanitoba.ca,-    RTT+0 ms    32769 XXXXXX
  # *130.179.16.67,-                                              UofM ID 1033
  #     protocol version 6
  #     100% of 32 requests ok    0.67+0+2000 ms RTT        0 ms queue wait
  
  # cdcc rtt
  # 03/10/06 09:20:37 CST  /usr/local/dcc/map
  # Re-resolve names after 11:20:37  Check RTTs after 09:35:37
  # 2463.84 ms threshold, 2781.32 ms average    2 total, 2 working servers
  IPv6 off
  
  electra.cc.umanitoba.ca,-    RTT+0 ms    32769 XXXXXX
  #  130.179.16.23,-                                              UofM ID 1032
  #      19% of 32 requests ok 2363.84+0 ms RTT            0 ms queue wait
  
  zaurak.cc.umanitoba.ca,-    RTT+0 ms    32769 XXXXXX
  # *130.179.16.67,-                                              UofM ID 1033
  #     protocol version 6
  #     100% of 32 requests ok    3.82+0+2000 ms RTT        0 ms queue wait
  
  # cdcc info
  # 03/10/06 09:22:01 CST  /usr/local/dcc/map
  # Re-resolve names after 11:20:37  Check RTTs after 09:35:37
  # 2463.84 ms threshold, 2781.32 ms average    2 total, 2 working servers
  IPv6 off
  
  electra.cc.umanitoba.ca,-    RTT+0 ms    32769 XXXXXX
  #  130.179.16.23,-                                              UofM ID 1032
  #      19% of 32 requests ok 2363.84+0 ms RTT            0 ms queue wait
  
  zaurak.cc.umanitoba.ca,-    RTT+0 ms    32769 XXXXXX
  # *130.179.16.67,-                                              UofM ID 1033
  #     protocol version 6
  #     100% of 32 requests ok    0.74+0+2000 ms RTT        0 ms queue wait
  
  # cdcc info
  # 03/10/06 09:26:09 CST  /usr/local/dcc/map
  # Re-resolve names after 11:20:37  Check RTTs after 09:35:37
  # 2463.84 ms threshold, 2781.32 ms average    2 total, 2 working servers
  IPv6 off
  
  electra.cc.umanitoba.ca,-    RTT+0 ms    32769 XXXXXX
  #  130.179.16.23,-                                              UofM ID 1032
  #      19% of 32 requests ok 2363.84+0 ms RTT            0 ms queue wait
  
  zaurak.cc.umanitoba.ca,-    RTT+0 ms    32769 XXXXXX
  # *130.179.16.67,-                                              UofM ID 1033
  #     protocol version 6
  #     100% of 32 requests ok    0.61+0+2000 ms RTT        0 ms queue wait
  
  # cdcc rtt
  # 03/10/06 09:27:33 CST  /usr/local/dcc/map
  # Re-resolve names after 11:27:33  Check RTTs after 09:42:33
  # 2100.94 ms threshold, 2670.82 ms average    2 total, 2 working servers
  IPv6 off
  
  electra.cc.umanitoba.ca,-    RTT+0 ms    32769 XXXXXX
  # *130.179.16.23,-                                              UofM ID 1032
  #      22% of 32 requests ok 1576.26+0 ms RTT            0 ms queue wait
  
  zaurak.cc.umanitoba.ca,-    RTT+0 ms    32769 XXXXXX
  #  130.179.16.67,-                                              UofM ID 1033
  #     protocol version 6
  #     100% of 32 requests ok    0.94+0+2000 ms RTT        0 ms queue wait
  
  # cdcc info
  # 03/10/06 09:27:46 CST  /usr/local/dcc/map
  # Re-resolve names after 11:27:33  Check RTTs after 09:42:33
  # 2100.94 ms threshold, 2670.82 ms average    2 total, 2 working servers
  IPv6 off
  
  electra.cc.umanitoba.ca,-    RTT+0 ms    32769 XXXXXX
  # *130.179.16.23,-                                              UofM ID 1032
  #      94% of 32 requests ok    0.58+0 ms RTT            0 ms queue wait
  
  zaurak.cc.umanitoba.ca,-    RTT+0 ms    32769 XXXXXX
  #  130.179.16.67,-                                              UofM ID 1033
  #     protocol version 6
  #     100% of 32 requests ok    0.94+0+2000 ms RTT        0 ms queue wait

-- 
-Gary Mills-    -Unix Support-    -U of M Academic Computing and Networking-



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