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Comment: DOCS-1929


The commands demonstrate how to configure the network settings in the /proc system. To ensure the settings persist across system reboots, be sure to configure the equivalent settings in the etc/sysctl.conf, or the network stack configuration file appropriate for your operating system.






The EUM processor requires the libaio library to be on the system. This library facilitates asynchronous I/O operations on the system. Note if you have a NUMA based architecture, then you are required to install the numactl package.

Install libaio on the host machine if it does not already have it installed. The following table provides instructions on how to install libaio for some common flavors of Linux operating system.

Use to libaio instuctions above).
Linux Flavor
Red Hat and CentOS

Use yum

 to install the library, such as:

  • yum install libaio
  • yum install numactl
FedoraInstall the library RPM from the Fedora website.

Use apt-get, such as:

  • sudo apt-get install libaio1
FedoraInstall the libaio RPM from the Fedora website.
  • sudo apt-get install numactl
DebianUse a package manager such as APT to install
the library (as described for the Ubuntu
instructions above).

Configure User Limits in Linux

AppDynamics recommends the following hard and soft per-user limits in Linux: 

  • Open file descriptor limit (nofile): 65535
  • Process limit (nproc): 8192

The following log warnings may indicate insufficient limits:

  • Warning in database log: "Could not increase number of max_open_files to more than xxxx".
  • Warning in server log: "Cannot allocate more connections".

To check your existing settings, as the root user, enter the following commands:

ulimit -S -n
ulimit -S -u

The output indicates the soft limits for the open file descriptor and soft limits for processes, respectively. If the values are lower than recommended, you need to modify them. 

Where you configure the settings depends upon your Linux distribution:  

  • If your system has a /etc/security/limits.d directory, add the settings as the content of a new, appropriately named file under the directory.
  • If it does not have a /etc/security/limits.d directory, add the settings to /etc/security/limits.conf. 
  • If your system does not have a /etc/security/limits.conf file, it is possible to put the ulimit command in /etc/profile. However, check the documentation for your Linux distribution for the recommendations specific for your system.  

To configure the limits: 

  1. Determine whether you have a /etc/security/limits.d directory on your system, and take one of the following steps depending on the result:
    • If you do not have a /etc/security/limits.d directory:
      1. As the root user, open the limits.conf file for editing:

      2. Set the open file descriptor limit by adding the following lines, replacing <login_user> with the operating system username under which the EUM Server runs:

        <login_user> hard nofile 65535
        <login_user> soft nofile 65535
        <login_user> hard nproc 8192
        <login_user> soft nproc 8192
    • If you do have a /etc/security/limits.d directory:
      1. As the root user, create a new file in the limits.d directory. Give the file a descriptive name, such as the following: 

      2. In the file, add the configuration setting for the limits, replacing <login_user> with the operating system username under which the EUM Server runs: 

        <login_user> hard nofile 65535
        <login_user> soft nofile 65535
        <login_user> hard nproc 8192
        <login_user> soft nproc 8192
  2.  Enable the file descriptor and process limits as follows: 
    1. Open the following file for editing:

    2.  Add the line:

      session required pam_limits.so
  3. Save your changes to the file. 

When you log in again as the user identified by login_user, the limits will take effect.