Caché High Availability Guide - InterSystems Documentation

Table of ContentsIntroduction ........................................................................................................................ 11 Write Image Journaling and Recovery .......................................................................... 31.1 Write Image Journaling ............................................................................................ 31.1.1 Image Journal ................................................................................................. 41.1.2 Two-Phase Write Protocol .............................................................................. 41.2 Recovery .................................................................................................................. 51.2.1 Recovery Procedure ........................................................................................ 61.3 Error Conditions ....................................................................................................... 71.3.1 If Recovery Cannot Complete (UNIX and OpenVMS) ................................. 81.3.2 Sample Recovery Errors ................................................................................. 91.3.3 Write Daemon Panic Condition .................................................................... 101.3.4 Write Daemon Errors and System Crash ...................................................... 101.3.5 Freeze Writes on Error ................................................................................. 101.3.6 Responding to a Freeze ................................................................................ 121.4 Limitations of Write Image Journaling .................................................................. 132 Backup and Restore ....................................................................................................... 152.1 Backup Integrity and Recoverability ..................................................................... 162.2 Importance of Journals ........................................................................................... 172.3 Backup Methods .................................................................................................... 182.3.1 External Backup ........................................................................................... 182.3.2 Online Backup .............................................................................................. 212.4 Configuring Caché Backup Settings ...................................................................... 232.4.1 Define Database Backup List ....................................................................... 242.4.2 Configure Backup Tasks ............................................................................... 242.4.3 Schedule Backup Tasks ................................................................................ 262.5 Managing Caché Online Backups .......................................................................... 272.5.1 Run Backup Tasks ........................................................................................ 272.5.2 View Backup Status ...................................................................................... 282.5.3 View Backup History .................................................................................... 282.5.4 Error Handling for Backups ......................................................................... 292.5.5 Backing Up Selected Globals and Routines ................................................. 292.6 Restoring from a Backup ....................................................................................... 302.6.1 Using the Backup History to Recreate the Database .................................... 30Caché High Availability Guideiii