Prerequisite Installation Steps

This document describes the steps you must perform prior to installing AtScale.

1. Provision hardware and install required operating system libraries that satisfy the minimum system requirements.

2. Download and verify the installer package.

   1. Download the RPM or DEB version of the latest installer package and package verification file for your target operating system.
   2. After downloading the installer package and verification file, make sure the package is valid by comparing the key returned by the sha256sum command to the key in the verification file.

\$ cat verification_file_name.sha256  
\$ sha256sum installer_package_filename.rpm

1. Disable limits on open files, CPU time, virtual memory, max user processes and file sizes. Use ulimit to remove the "atscale" user limits for the following:

   1. open files - unlimited or 65536.
   2. cpu time - unlimited
   3. virtual memory - unlimited
   4. max user processes - unlimited or 65536.
   5. file size - unlimited

   If there are limits, work with your system administrator to remove each limit in a way that will survive a restart of the host. Failure to raise these limits will prevent various AtScale services from starting. Aditionally, fully disabling these limits will allow the AtScale engine to achieve the best possible performance when under heavy load.