IJ15758: INCREASE TCP_MAXQUEUELEN DEFAULT VALUE TO STOP CONNECTION LOSS APPLIES TO AIX 7100-05

APAR status

• Closed as program error.

Error description

• The scp or sftp will transfer an arbitrary amount of data
  and then fail with below message during file transfer
  from one Data center-to-Date center over WAN link:
  
  packet_write_poll: Connection to <IP Address> port 22:
  Broken pipe
  

Local fix

• Raise the tcp_maxqueuelen to higher value which is
  determined by
  tcp_recvspace/mss.
  For ex. en2.tcp_recvspace=2097152 /1500 MTU (1460 MSS)=
  1436
  approximate to 1500
  
  so choose a value =>1500
  
  To make the value permanent, run the following command.
  no -p -o tcp_maxqueuelen= 1500
  

Problem summary

• scp/sftp/ftp fail after transferring arbitrary amount of data
  due to Connection loss.
  netstat -p tcp | grep "max assembly queue depth"
  shows connection dropped .
  

Problem conclusion

• Updated the default length of reassembly queue.
  

Temporary fix

Comments

• 6100-09 - use AIX APAR IJ15760
  7100-04 - use AIX APAR IJ15834
  7100-04 - use AIX APAR IJ15834
  7100-05 - use AIX APAR IJ15758
  7200-01 - use AIX APAR IJ14087
  7200-02 - use AIX APAR IJ15989
  7200-03 - use AIX APAR IJ15759
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

  IJ14087

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  AIX V7.1

• Fixed component ID

  5765H4000

Applicable component levels

• R710 PSY U883458

     UP19/05/02 I 1000