LTO Tape Drive Cleaning
LTO Tape Drive Cleaning
Over time all tape drives require cleaning via dedicated cleaning tapes. The average cleaning tape can be used up to 50 times before it is used up and considered “expired”. Once a cleaning tape is expired it is no longer viable and needs to be discarded. Cleaning tapes are considered consumable items that customers must provide in order to keep their tape drives functioning properly.
There are two fundamental cleaning processes that can be performed. The first, and most common, is called a Reactive Drive Cleaning. The Reactive drive cleaning happens when a tape drive requests a clean while it’s being used. The second type of cleaning is called a Proactive Drive Cleaning. The Proactive drive cleaning is performed after a predetermined amount of Read/Write hours the drive has performed or simply a calendar based schedule that performs the cleaning after so many hours, days, or weeks. One thing to consider is that HP branded LTO drives require proactive drive cleaning to be enabled on a minimum of every 400 hours of Writing. This is due to the HP branded LTO drives disabling the reactive posting of cleaning tape alerts if only writing is being performed. IBM branded LTO drives do not have this same limitation.
LTO Tape Drives report reactive cleaning requests via specific Tape Alerts. A Tape Alert 20 is a “Clean Now” event meaning that an immediate cleaning is required. A Tape Alert 21 is a “Clean Periodic” event meaning that the tape drive can still function but you should clean it the next time you get a chance. A Tape Alert 22 is an “Expired Cleaning Media” event that gets reported when an expired cleaning tape is loaded into a drive.
The drive cleaning process can be automatically managed by either the Tape Library or the Application Software. This is usually referred to as “Library Managed” or “Application Managed” drive cleaning. Listed below are both types of cleaning management along with their pro’s and con’s. It’s up to the system administrator to decide which type of drive cleaning management they should leverage given the requirements and limitations of their ecosystem.
Library Managed Drive Cleaning
When library managed drive cleaning is used the library performs the drive cleaning process and manages the storage of the cleaning tapes. The library automates the movement of cleaning tapes in and out of the drives as required based on the cleaning schedule defined. Specific storage elements have to be defined as “Cleaning Slots” for the cleaning tapes to reside within the library. When library managed cleaning is enabled the majority of the cleaning processes performed will be executed in a “reactive” manner. Some but not all libraries have the ability to setup a proactive cleaning schedule based on hours of Read/Write the drives accrue. The primary challenges with using library Managed Drive Cleaning is that you must import and export the cleaning tapes as cleaning media. If you do not import the cleaning tapes as cleaning media the library will not consider it cleaning tapes and will not be able to leverage it when a cleaning process is required. We usually advise to use Library Managed Cleaning only if the Application Software cannot manage the drive cleaning process its self.
Application Managed Drive Cleaning
When the Application Software manages the drive cleaning all cleaning process are coordinated and executed by the Application Software. It is highly suggested to leverage Application Software managed cleaning because it usually allows for more refined cleaning schedules to be defined. The other advantage is that the cleaning tapes do not have to be located in specific cell locations within the library. Cleaning tapes are usually identified by their media barcode label number so as long as the cleaning tape is inside the library the Application Software can use the tape as needed for cleaning processes.
At a bare minimum a reactive drive cleaning process (Library or Application Managed) should be configured to properly clean the drives as needed. Cleaning tapes can be manually mounted into the drives if need be but that requires manual intervention via the library GUI or Application Software to perform. If you need more information on how to configure library managed cleaning please reference the User’s Guide for the Quantum Tape Library.
If you want to setup a proactive drive cleaning schedule based on drive usage it is recommended that you use 400 Read/Write Hours as a time based schedule or three separate Tape Alerts as an event based schedule. Defining a schedule with less Read/Write Hours or less Tape Alert events to trigger proactive cleaning usually does not improve the drive performance and will only use up your cleaning tapes faster than they should be. If you need more information on how to configure application managed cleaning contact your application software provider.