Preventive Service Planning
This document provides information that describes IBM Tivoli Storage Manager for System Backup and Recovery SysBack's (SysBack) support and usage of tape drives.
SysBack does not provide support for any particular tape drive. Instead, SysBack uses standard IOCTL commands to communicate with the drives. SysBack will execute read or write operations until the physical end of tape is reached. At that point, SysBack issues an eject command and waits for the next tape to be loaded. A tape may be loaded via human intervention, by the autoloading mechanism of the device, or via a library device mechanism.
Therefore, SysBack can utilize any tape drive device that is natively supported by the AIX operating system. SysBack can also support any tape drive device that is recognized by AIX when using device drivers supplied with the tape drive device. E.g. As long as AIX recognizes the tape device and configures it to have a /dev/rmtX name; SysBack can read and write to that device.
Tape drives that are a part of a library device require extra consideration. If the library is a type commonly referred to as a “sequential auto loader”, the autoloading mechanism of the library device will load the next tape for SysBack to use once SysBack has issued an eject command to the tape drive. If the library device is not an autoloader, it will have a separate robotic mechanism to manipulate tape movement. In those situations, a device name must be configured in AIX to represent that library device. However, SysBack does not provide any special support for the library device mechanism. Also, SysBack will not directly communicate with the library device name. Therefore, after SysBack has issued an eject command to the tape drive, the customer must issue any commands required to manipulate the library device for tape movement. These commands may be issued manually or via a script. Scripts to manipulate library device movements can be integrated into SysBack operations via special End of Tape Processing utilities provided by the product.
Because of this design, SysBack can work with any tape device on the market, by any vendor, so long as:
- AIX can configure a device name for it
- It functions as a sequential autoloading device or,
- The device driver provides an external command line interface for issuing commands to control tape movement
An additional note about tape drive support:
Using certain newer devices like the IBM 3592, which provide encryption functions, can cause problems if the application using them does not formally support that feature of the drive.
SysBack will support these types of drives as previously described. However, SysBack does not support the mechanisms and features that provide encryption. SysBack’s support statement related to tape drive encryption is:
SysBack does not presently support any form of drive enabled encryption, nor does it provide integration with any software or hardware encryption methods. This does not preclude the use of transparent encryption. For example: using the TS1120 (IBM 3592) with “System” or “Library managed” encryption enabled. However, those tapes created with transparent encryption methods:
- Can not be used for system boot due to system firmware limitations
- Can not be used for system recovery (even with alternate boot media)
- Can not be accessed during outages to the encryption system
Therefore, the use of transparent encryption methods in conjunction with SysBack should be done so with extreme caution to ensure that the data on the tapes can be recovered during a system outage.