5 1 0:Informix Restore

From SEPsesam

Welcome to the latest SEP sesam documentation version 5.1.0 Apollon. For previous documentation version(s), check documentation archive.


SEP sesam online backup for Informix (SIB) provides the Backup Services API (XBSA) between Informix and SEP sesam for saving Informix data to the SEP sesam Server. XBSA specifies the access from Informix ON-Bar utility to a backup application. During backups and restores, ON-Bar uses XBSA to exchange the data from specified storage spaces (dbspaces) or logical-log files. SEP sesam manages all storage media, while ON -Bar decides which data to back up or restore.

Configuring ON-Bar restore

During restore, the Informix ON-Bar utility provides the interface to the databases and performs extraction and insertion of the data. The shared XBSA library translates the Informix names passed by ON-Bar into SEP sesam Server saveset for retrieval from the SEP sesam Server database and restoration to Informix. Note that you have to verify that the storage devices and files used in the backups are available for restore.

It is possible to restore backed up storage spaces (physical restore), logical log files (logical restore), or both (combined restore). To perform an Informix restore, you have have to run onbar -r commands as the root user or the Informix user.

Physical restore

Physical restore replaces lost or corrupted storage spaces (permanent or temporary dbspaces, etc.) from the SEP sesam backup media. If a critical storage space is damaged due to a disk failure or corrupted data, Informix Dynamic Server (IDS) is taken offline. If the IDS is not taken offline in such cases, it is possible to restore any non-critical storage spaces.

setenv SESAM_SERVER jupiter 
setenv INFORMIXDIR /usr/informix 
setenv ONCONFIG onconfig.std
onbar -r -p

Logical restore

It is possible to restore and roll forward logical logs by using onbar -r -l command. Logical restores recover the server transactions that have been backed up since the last storage space backup, followed by forwarding the logical logs that were backed up for the storage spaces. If different backups are running, the transactions will continue to be written to the current log file for each space during the backup. Note that the logical restore applies only to those storage spaces that are already physically restored.

onbar -r -l

Combined restore

Combined restores allow you to run a single command to perform a physical restore immediately followed by a logical restore. For finer control, use the onbar -b -l -s command to salvage the logs, then the onbar -r -p command to perform only a physical restore, and then the onbar -r -l command to perform only a logical restore.

onbar -r

Point-in-time restore

Point-in-time restores involve performing a whole-system, physical restore of Informix data from a whole-system-backup to a specific point in time (instead of default, which is the time of the last Informix backup). A point-in-time restore is specified by including the -t option (time) in the onbar command. If you use this command, you must restore all storage spaces to the same point in time.

setenv SESAM_SERVER jupiter
onbar -r -t time -w -p

There are two different types of restore you can perform in dependence of IDS current operating mode (quiescent, online or offline). If the server is in quiescent mode or is online, you can perform a warm restore. In this case you have to use the -O option to restore an online storage space. Otherwise, if the server is in offline mode, the restore operation is called a cold restore.

For example, logical log:

onbar -l -L 0 dbspace01

ON-Bar restore commands examples

You must run the onbar -r command with the appropriate options to start a database or logical logs restore (by default, ON-Bar restores the latest backup):

  • Complete restore of the database (cold restore)
onmode -ky   - Database shutdown
onbar -r -w  - Restore of all data
  • Restore of the down dbspaces and corresponding logical logs (cold)
onbar -r
  • Restore of the down dbspaces without logical logs (cold)
onbar -r -p
  • Restore of single dbspaces
onbar -r <dbspace_name_1> <dbspace_name_2> 
  • Logical logs restore (for dbspaces, wich have been restored physically)
onbar -r -l
  • If the chunk areas have been deleted, you have to use -O option. This forces the recreation of chunk files that no longer exist.
onbar -r ... -O
  • Occasionally no checkpoint is written because of the missing chunk. This can be avoided by using the command
onmode -O

or by shutting down the database with a cold restore, as described in the first example above.

For details on other onbar restore commands, see Restoring data with onbar.

Known issues

If you have problems with Informix, check the Troubleshooting Guide.

See also

Informix BackupInformix Configuration

External reference

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