On October 19, 2021, we have enabled single-sign-on for our Plesk Support Center to provide a seamless login/account experience. This implies that you’ll be able to use a single account across any of our web-facing properties.
If you had already registered your account at Plesk 360 (formerly known as My Plesk) please use one for login. Otherwise please re-register it using the same email address as your existing Zendesk login (support account). It’s essential that you use the same email address on our support center to ensure that your tickets stay attached to the same account.

High CPU usage for "sa-learn" and "spamtrain" processes in a server with Plesk

Follow

Comments

10 comments

  • Avatar
    Alexander Bien

    Are you sure that we need to modify 60sa-update in order to change high cpu from sa-learn?

    This pstreelog output (C7, P17.8.x) would suggest otherwise:

    |-anacron---run-parts-+-50plesk-daily---sw-engine---sw-engine---spamtrain---su---sa-learn

    I couldnt find any mentioning of sa-learn in sa-update either. Please advise.

    0
    Comment actions Permalink
  • Avatar
    Robert Asilbekov

    @Alexander Bien

    Thank you for the feedback. The article has been updated.

    0
    Comment actions Permalink
  • Avatar
    Peter Debik

    On CentOS

    echo "/bin/nice -19 /usr/bin/perl -T -w /usr/bin/sa-learn.orig $@" > /usr/bin/sa-learn

    must be executed as

    echo "/bin/nice -19 /usr/bin/perl -T -w /usr/bin/sa-learn.orig \$@" > /usr/bin/sa-learn

    because else, the "$@" will not be exported into /usr/bin/sa-learn.

    0
    Comment actions Permalink
  • Avatar
    Anton Maslov

    Peter, article updated! Thank you for report!

    0
    Comment actions Permalink
  • Avatar
    Bbennett

    Trying to disable and get the error: 

    mv /etc/cron.daily/60sa-update /root
    mv: cannot stat ‘/etc/cron.daily/60sa-update’: No such file or directory

    0
    Comment actions Permalink
  • Avatar
    Ivan Postnikov

    Hello Bbennett

    Did you execute this command as a root user?

    The 60sa-update exists on my test server and the issue wasn't reproduced:

    # stat /etc/cron.daily/60sa-update
    File: '/etc/cron.daily/60sa-update'
    Size: 448 Blocks: 8 IO Block: 4096 regular file
    Device: 40f0b681h/1089517185d Inode: 409504 Links: 1
    Access: (0755/-rwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root)
    Access: 2020-01-23 13:44:39.000000000 +0700
    Modify: 2020-01-23 13:44:39.000000000 +0700
    Change: 2020-01-27 20:52:40.452451535 +0700
    Birth: -

     

    # plesk -v
    Product version: Plesk Obsidian 18.0.23.1
    OS version: CentOS 7.5.1804 x86_64

     

    0
    Comment actions Permalink
  • Avatar
    Jair Cueva Junior

    In Ubuntu 18.04 this wrapper scripts was failing due to a slightly difference in the path of "nice" command, it should be: /usr/bin/nice

    Thanks for exposing this approach, it has opened my mind for possibilities!

    0
    Comment actions Permalink
  • Avatar
    Nelson Leiva

    Hi Jair Cueva Junior,

    The article has been updated. Thank you for noticing that!

    0
    Comment actions Permalink
  • Avatar
    Michael Fryd

    When importing large email accounts for new clients, my server was bogged down, even with sa-learn running with low priority. 

    We don't see single instances of sa-learn using a lot of resources, we see many instances of sa-learn running sequentially.



    My solution was to write a script that checks the system load average.  If the load is getting high, it pauses before running sa-learn.  This helps keep the load from getting too high.  If the load doesn't come down, or the load is too high, it doesn't bother running sa-learn.  This seems to be OK. I suspect the message that were skipped will be examined on a subsequent run.

     

    Here's my replacement for /usr/bin/sa-learn:

     

    #!/bin/bash
    #
    # replacement for /usr/bin/sa-learn
    # hack to keep sa-learn process from using too many resources
    # created 6/26/2020
    #
    # PLESK periodically calls /usr/bin/sa-learn to train spam assassin on recent mail.
    # if large amounts of new mail are present (perhaps a large external email
    # account was recently imported) the i/o burden can bog down the server. We have
    # seen load averages above 300.
    #
    # our solution is multi-pronged.
    # first, we simply don't run sa-learn if the load avergage is too high.
    # secondly, if the load average is starting to get high, we pause a little bit before
    # starting sa-learn
    # finally, if we do start sa-learn, we use nice to run it at a low priority.
    #
    # We have moved the original sa-learn script to /usr/bin/sa-learn.orig
    #
    # Note: we truncate the load average and look at only the integer portion.
    #
    # -Michael Fryd (michael@fryd.com) 6/26/2020
    #


    PUNT_LOAD_LIMIT=4 # If the load is higher than this we exit and don't run sa-learn.orig
    WAIT_LOAD_LIMIT=3 # if the load is higher than this, but below PUNT_LOAD_LIMIT, we delay before running
    SLEEP_TIME=0.4 # how long to delay (in seconds)
    MAX_ATTEMPTS=2 # max number of times to wait for load to come down before punting


    count=0
    while [ "$count" -lt "$MAX_ATTEMPTS" ]; do
    # get the integer portion of the current 1 minute load average
    load=$(uptime | awk -F: '{print $5}' | awk -F"," '{print $1}' | tr -d '[:space:]' | cut -c1) # Poll Load

    # if the load is greater than the punt limit, give up. Don't wait, and no
    # additional passes
    if [[ "$load" -gt "$PUNT_LOAD_LIMIT" ]]; then
    exit 0; # give up, don't run sa-learn.orig at this time
    fi

    # if the load is low, then run sa-learn.orig at low priority, otherwise pause, then loop again
    if [[ "$load" -lt "$WAIT_LOAD_LIMIT" ]]; then
    /bin/nice -n 19 /usr/bin/perl -T -w /usr/bin/sa-learn.orig $@
    exit 0; # If successful
    else
    sleep $SLEEP_TIME;
    fi;
    (( count++ ))
    done;

    0
    Comment actions Permalink
  • Hi Michael Fryd,

    Thanks for such useful script whenever a mail importing is happening, it may be useful for other users.

    0
    Comment actions Permalink

Please sign in to leave a comment.

Have more questions? Submit a request