error log and server down report - Running short of concurrent connections

Discussion in 'Install/Configuration' started by Strats, Dec 11, 2013.

  1. Strats

    Strats New Member

    Hi, I'm new to litespeed, I currently run the LSWS 4-CPU license and lately that traffic has increased and I'm taking some alerts from my server monitor (server down) and I notice that the error log has lots of entries like:

    Running short of concurrent connections.
    Current available connections: 399, real in-use: 1655

    The server is getting lots of concurrent:
    root@server [~]# netstat -an | grep 80 | grep ESTA | wc
    1372 8232 122108
    root@server [~]#

    Is this related to the litespeed tuning configuration please? I currently have:
    Max Connections: 2000
    Connection Timeout (secs): 120
    Max Keep-Alive Requests: 1000

    Thanks in advance for your advices!
  2. NiteWave

    NiteWave Administrator

    increase:
    Max Connections: 2000
    see if any improvement

    also check kernel's tcp/ip settings, for example conntrack
    #sysctl -a|grep conntrack
    if anything abnormal
  3. Strats

    Strats New Member

    Hi NiteWave,

    I have check kernel settings, seems OK and I have increased Max Connections from 2000 to 3000.

    I will update this topic once I have results.

    Thanks
  4. NiteWave

    NiteWave Administrator

    please take a screenshot of
    lsws webadmin ->
    Actions ->
    Real-Time Stats

    best do it in busiest time, so know a lot about the server's running status
  5. Strats

    Strats New Member

    OK NiteWave, I will take the screenshot as soon server gets really busy again (now it's not the pick time) and I will post it here.

    Again, thanks a lot for your help!
  6. Strats

    Strats New Member

    This is a screenshot of the real stats while
    # netstat -an | grep 80 | grep ESTA | wc
    1069 6414 95141

    Currently I don't get the "Running short of concurrent connections" error. Later I will try to catch the server in higher traffic to take another screenshot.

    Thanks NiteWave

    Attached Files:

  7. Strats

    Strats New Member

    Hi NiteWave,

    I got the server on the pick traffic time and again I have the "Running short of concurrent connections" problem (Current available connections: 796, real in-use: 3522). This happens when traffic gets to the following numbers:

    # netstat -an | grep 80 | grep ESTA | wc
    2045 12270 182005

    I have increased max connections to 4000 but it didn't help. I attach the screenshot of real-stats

    Thanks

    Attached Files:

  8. NiteWave

    NiteWave Administrator

    the "Http Out" is 96,335 KB
    looks like your 1Gbit NIC(if it is) has reached its limit!
    I believe it's related to "Running short of concurrent connections"

    you've to increase your server's network capability, for example add another 1Gbit NIC to the server or add another server or change to 10Gbit NIC to handle the traffic.

    yet good news for you, have hit the 1Gbit limit and also a witness to lsws, it can handle such traffic well
  9. Strats

    Strats New Member

    Hi NiteWave,

    Thank you for helping me targeting the cause of this issue. Yes, indeed this is a witness to lsws, it is amazing how well it can handle such traffic, congratulations, I'm sure no other web server could have ever done it successfully in numbers like the one I attach :)

    # netstat -an | grep 80 | grep ESTA | wc
    2975 17850 264776

    Have a nice day,
    Stratos

    Attached Files:

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