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Wordpress What does this look like to you? admin-ajax.php loads

Discussion in 'Blogs & CMS usage' started by Matt Williams, Dec 17, 2015.

  1. Matt Williams

    Matt Williams WordPress Fanatic

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    Screenshot: Screenshot by Lightshot - happens everyday at the same exact time and for the life of me, I can not figure out what is causing this spike. The CPU load shoots to 30+ and lasts for 15-20 minutes and everything goes back to normal again. My first thought was a plugin so I disabled them all for 24 hours and it still happen - I monitored traffic with How to sniff HTTP traffic from the command line on Linux - Xmodulo and it was moving extremely fast and I monitored with How to sniff HTTP traffic from the command line on Linux - Xmodulo and it said the file being hit the hardest was admin-ajax.php so I disabled that from within functions.php and it still didn't do anything

    Think DDoS maybe? But why such a short burst and then just die and go back to normal. A DDoS is usually continuous until it crashes the VPS but this VPS doesn't crash even under a 30+ load average - It slows down to a crawl but it doesn't crash.
     
  2. eva2000

    eva2000 Administrator Staff Member

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    WordPress Heartbeat and heavy admin-ajax.php usage - InMotion Hosting ;)

    centmin.sh menu option 22 wordpress auto installer originally had a heartbeat control plugin as installed but not activated centminmod/wpsetup.inc at 123.09beta01 · centminmod/centminmod · GitHub :)

    but updated version has it disabled, unless centmin.sh has WPPLUGINS_ALL=y
     
  3. Matt Williams

    Matt Williams WordPress Fanatic

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    Did that and didn't work - Then I edited the functions.php file and added:

    I wanted to completely stop it and the plugin only "controls" it but even code didn't work
     
  4. eva2000

    eva2000 Administrator Staff Member

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    you sure, from site
     
  5. eva2000

    eva2000 Administrator Staff Member

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  6. eva2000

    eva2000 Administrator Staff Member

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    Diagnose admin-ajax.php Causing Slow Load Times in WP
    tracking down admin-ajax.php usage
     
  7. Matt Williams

    Matt Williams WordPress Fanatic

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    Bingo! Brian, the person who posted that post referenced above is a good friend, I even read this post awhile ago!

    Screenshot by Lightshot

    The plugin "Thrive Leads" was the issue - Disabling it did nothing - Deleting it did the trick.
     
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  8. eva2000

    eva2000 Administrator Staff Member

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    haha small world :D
     
  9. Matt Williams

    Matt Williams WordPress Fanatic

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    Couldn't possibly be an issue with Admin-Ajax. Happened 3 times tonight - VPS was down 3 times and all 3 times looked exactly the same as the others.
    So I decided to break out the trusted Siege tool and do a little bombing myself on this site and see if I can come close to replicating what is happening..

    Test run:
    Code:
    Lifting the server siege...      done.
    
    Transactions:                  53653 hits
    Availability:                 100.00 %
    Elapsed time:                 599.82 secs
    Data transferred:            1057.02 MB
    Response time:                  7.82 secs
    Transaction rate:              89.45 trans/sec
    Throughput:                     1.76 MB/sec
    Concurrency:                  699.26
    Successful transactions:       52940
    Failed transactions:               1
    Longest transaction:           25.26
    Shortest transaction:           0.14
    The VPS never failed, Never went down at all. The CPU reached 30+ but still didn't fail. I think im going to enable DDoS protection on this VPS...

    53K hits in 10 minutes without a break and never failed - I give that a (y) ( using Redis ) :whistle:
     
  10. eva2000

    eva2000 Administrator Staff Member

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    while siege is nice, siege isn't fool proof or 100% accurate - so passing siege doesn't mean much as those tests are are with 100% uniform requests. Real world traffic doesn't observe such uniform and timely requests, so you need to investigate