![[Contents]](FIGURE/CONTENT.GIF)
Scalable Database Server, HiRDB Version 8 Description
![[Glossary]](FIGURE/GLOSS.GIF)
![[Index]](FIGURE/INDEX.GIF)
![[Back]](FIGURE/FRONT.GIF)
![[Next]](FIGURE/AFTER.GIF)
A file in which system log information is stored is called a system log file. System log refers to information on the history of database updating, which is commonly called a log (or journal in mainframe terminology). HiRDB collects system log information in system log files for use:
The HiRDB administrator should create system log files as a safeguard against failures, as well as for acquiring statistical information.
HiRDB operates with logical units of system log files called file groups. A file group consists of either one or two system log files. A configuration of two system log files is called a duplexed system log file. The respective system log files are distinguished by referring to them as file A and file B. When duplexed system log files are used, HiRDB acquires the same contents into both log files. Thus, if one of the files should fail, the other file can be used, thus maintaining system reliability. Figure 6-2 shows the organization of system log files.
Figure 6-2 Organization of system log files
![[Figure]](FIGURE/ZU060020.GIF)
The pdloginit command is used to create system log files. Additionally, you specify the following HiRDB system definition operands to create an environment in which the system log files can be used:
For details about designing and creating system log files, see the HiRDB Version 8 Installation and Design Guide. For details about using the system log files, see the HiRDB Version 8 System Operation Guide.
All Rights Reserved. Copyright (C) 2007, Hitachi, Ltd.