You can keep your system available by effectively planning and managing fixes and installing new releases.
To reduce the amount of time your system is unavailable, you should ensure that you have a fix management strategy in place. If you stay current on what fixes are available and install them on a routine basis, you will have fewer problems. Be sure that you apply fixes as frequently as you have decided is appropriate for your business needs. For recommendations on how to create a fix management strategy, see Plan your fix management strategy.
Individual fixes can be delayed or immediate. Delayed fixes can be loaded and applied in two separate steps. They can be loaded while your system runs and then applied the next time you restart your server. Immediate fixes do not require you to restart your system in order for them to take effect, which eliminates the need for downtime. Immediate fixes may have additional activation steps that are described in full in the cover letter that accompanies the fix. For more information on how to apply fixes, see Install fixes.
You are required to power down your system when you upgrade to a new version of i5/OS™. To minimize the amount of time a software upgrade takes, it is important that you plan your installation carefully. For information on the planning process, see Upgrading or replacing i5/OS and related software.