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We will cover some basic backup and recovery strategies. These are intended to be robust but simple enough to set up. For a large scale production site you would probably need to create your own backup strategies (in particular full dumps from oracle, while easy to set up, are far from the best solution).
There are three basic things which need to be backed up, the database data, the server source tree, and the acs-content-repository (which is in the server source tree).
The purpose of backup is to enable recovery. Backup and recovery are always risky; here are some steps that minimize the chance recovery is necessary:
Store everything on a fault-tolerant disk array (RAID 1 or 5 or better).
Use battery backup.
Use more reliable hardware, such as SCSI instead of IDE.
These steps improve the chances of successful recovery:
Store backups on a third disk on another controller
Store backups on a different computer on a different network in a different physical location. (Compared to off-line backup such as tapes and CDRs, on-line backup is faster and more likely to succeed, but requires maintenance of another machine.)
Plan and configure for recovery from the beginning.
Test your recovery strategy from time to time.
Make it easy to maintain and test your recovery strategy, so that you are more likely to do it.
OpenACS installations comprise files and database contents. If you follow the reference install and put all files, including configuration files, in /var/lib/aolserver/service0/, and back up the database nightly to a file in /var/lib/aolserver/service0/database-backup, then you can apply standard file-based backup strategies to /var/lib/aolserver/service0
This section describes how to make a one-time backup and restore of the files and database. This is useful for rolling back to known-good versions of a service, such as at initial installation and just before an upgrade. First, you back up the database to a file within the file tree. Then, you back up the file tree. All of the information needed to rebuild the site, including the AOLserver config files, is then in tree for regular file system backup.
Back up the database to a file.
Download the backup script. Save the file export-oracle.txt as /tmp/export-oracle.txt
Login as root. The following commands will install the export script:
[joeuser ~]$ su - [root ~]# cp /tmp/export-oracle.txt /usr/sbin/export-oracle [root ~]# chmod 700 /usr/sbin/export-oracle
Setup the export directory; this is the directory where backups will be stored. We recommend the directory /ora8/m02/oracle-exports.
[root ~]# mkdir /ora8/m02/oracle-exports [root ~]# chown oracle:dba /ora8/m02/oracle-exports [root ~]# chmod 770 /ora8/m02/oracle-exports
Now edit /usr/sbin/export-oracle and change the SERVICE_NAME and DATABASE_PASSWORD fields to their correct values. If you want to use a directory other than /ora8/m02/oracle-exports, you also need to change the exportdir setting.
Test the export procedure by running the command:
[root ~]# /usr/sbin/export-oracle mv: /ora8/m02/oracle-exports/oraexport-service_name.dmp.gz: No such file or directory Export: Release 8.1.6.1.0 - Production on Sun Jun 11 18:07:45 2000 (c) Copyright 1999 Oracle Corporation. All rights reserved. Connected to: Oracle8i Enterprise Edition Release 8.1.6.1.0 - Production With the Partitioning option JServer Release 8.1.6.0.0 - Production Export done in US7ASCII character set and US7ASCII NCHAR character set . exporting pre-schema procedural objects and actions . exporting foreign function library names for user SERVICE_NAME . exporting object type definitions for user SERVICE_NAME About to export SERVICE_NAME's objects ... . exporting database links . exporting sequence numbers . exporting cluster definitions . about to export SERVICE_NAME's tables via Conventional Path ... . exporting synonyms . exporting views . exporting stored procedures . exporting operators . exporting referential integrity constraints . exporting triggers . exporting indextypes . exporting bitmap, functional and extensible indexes . exporting posttables actions . exporting snapshots . exporting snapshot logs . exporting job queues . exporting refresh groups and children . exporting dimensions . exporting post-schema procedural objects and actions . exporting statistics Export terminated successfully without warnings.
PostgreSQL. Create a backup file and verify that it was created and has a reasonable size (several megabytes).
[root root]# su - service0 [service0 service0]$ pg_dump -f /var/lib/aolserver/service0/database-backup/before_upgrade_to_4.6.dmp service0 [service0 service0]$ ls -al /var/lib/aolserver/service0/database-backup/before_upgrade_to_4.6.dmp -rw-rw-r-x 1 service0 service0 4005995 Feb 21 18:28 /var/lib/aolserver/service0/database-backup/before_upgrade_to_4.6.dmp [service0 service0]$ exit [root root]# su - service0 pg_dump -f /var/lib/aolserver/service0/database-backup/before_upgrade_to_4.6.dmp openacs-dev ls -al /var/lib/aolserver/service0/database-backup/before_upgrade_to_4.6.dmp exit
Back up the file system. Back up all of the files in the service, including the database backup file but excluding the auto-generated supervise directory, which is unneccesary and has complicated permissions.
In the tar command,
c create a new tar archive
p preserves permissions.
s preserves file sort order
z compresses the output with gzip.
The --exclude clauses skips some daemontools files that are owned by root and thus cannot be backed up by the service owner. These files are autogenerated and we don't break anything by omitting them.
The --file clause specifies the name of the output file to be generated; we manually add the correct extensions.
The last clause, /var/lib/aolserver/service0/, specifies the starting point for backup. Tar defaults to recursive backup.
[root root]# su - service0 [service0 service0]$ tar -cpsz --exclude /var/lib/aolserver/service0/etc/daemontools/supervise \ --file /tmp/service0-backup.tar.gz /var/lib/aolserver/service0/ tar: Removing leading `/' from member names [service0 service0]$
Suffer a catastrophic failure on your production system. (We'll simulate this step)
[root root]# svc -d /service/service0
[root root]# mv /var/lib/aolserver/service0/ /var/lib/aolserver/service0.lost
[root root]# rm /service/service0
rm: remove symbolic link `/service/service0'? y
[root root]# ps -auxw | grep service0
root 1496 0.0 0.0 1312 252 ? S 16:58 0:00 supervise service0
[root root]# kill 1496
[root root]# ps -auxw | grep service0
[root root]# su - postgres
[postgres pgsql]$ dropdb service0
DROP DATABASE
[postgres pgsql]$ dropuser service0
DROP USER
[postgres pgsql]$ exit
logout
[root root]#Restore the operating system and required software. You can do this with standard backup processes or by keeping copies of the install material (OS CDs, OpenACS tarball and supporting software) and repeating the install guide. Recreate the service user (service0).
Restore the OpenACS files and database backup file.
[root root]# su - service0 [service0 service0]$ cd /var/lib/aolserver [service0 aolserver]$ tar xzf /tmp/service0-backup.tar.gz [service0 aolserver]$ chmod -R 775 service0 [service0 aolserver]$ chown -R service0.web service0
Restore the database
Oracle.
Set up a clean Oracle database user and tablespace with the same names as the ones exported from (more information).
Invoke the import command
imp service0/service0 FILE=/var/lib/aolserver/service0/database-backup/nighty_backup.dmp FULL=YPostgres. If the database user does not already exist, create it.
[root root]# su - postgres
[postgres ~]$ createuser service0
Shall the new user be allowed to create databases? (y/n) y
Shall the new user be allowed to create more new users? (y/n) y
CREATE USER
[postgres ~]$ exit
Because of a bug in Postgres backup-recovery, database objects are not guaranteed to be created in the right order. In practice, running the OpenACS initialization script is always sufficient to create any out-of-order database objects. Next, restore the database from the dump file. The restoration will show some error messages at the beginning for objects that were pre-created from the OpenACS initialization script, which can be ignored.
[root root]# su - service0 [service0 ~]$ createdb service0 CREATE DATABASE [service0 ~]$ psql -f /var/lib/aolserver/service0/packages/acs-kernel/sql/postgresql/postgresql.sql service0 (many lines omitted) [service0 ~]$ psql service0 < /var/lib/aolserver/service0/database-backup/database-backup.dmp (many lines omitted) [service0 ~]$ exit [postgres ~]$ exit logout
Activate the service
[root root]# ln -s /var/lib/aolserver/service0/etc/daemontools /service/service0 [root root]# sleep 10 [root root]# svgroup web /service/service0
The recommended backup strategy for a production sit is to use an automated script which first backs up the database to a file in /var/lib/aolserver/service0/database-backup and then backs up all of /var/lib/aolserver/service0 to a single zip file, and then copies that zip file to another computer.
Make sure that the manual backup process described above works.
Customize the default backup script. Edit /var/lib/aolserver/service0/etc/backup.sh with your specific parameters.
Make sure the file is executable:
chmod +x backup.sh
Set this file to run automatically by adding a line to root's crontab. (Typically, with export EDITOR=emacs; crontab -e.) This example runs the backup script at 1:30 am every day.
30 1 * * * * sh /var/lib/aolserver/service0/etc/backup.shCVS-only backup is often appropriate for development sites. If you are already using CVS and your data is not important, you probably don't need to do anything to back up your files. Just make sure that your current work is checked into the system. You can then roll back based on date - note the current system time, down to the minute. For maximum safety, you can apply a tag to your current files. You will still need to back up your database.
Note that, if you did the CVS options in this document, the /var/lib/aolserver/service0/etc directory is not included in cvs and you may want to add it.
[root root]# su - service0 [service0 service0]$ cd /var/lib/aolserver/service0 [service0 service0]$ cvs commit -m "last-minute commits before upgrade to 4.6" cvs commit: Examining . cvs commit: Examining bin (many lines omitted) [service0 service0]$ cvs tag before_upgrade_to_4_6 cvs server: Tagging bin T bin/acs-4-0-publish.sh T bin/ad-context-server.pl (many lines omitted) [service0 service0]$ exit [root root]# su - service0 cd /var/lib/aolserver/service0 cvs commit -m "last-minute commits before upgrade to 4.6" cvs tag before_upgrade_to_4_6 exit
To restore files from a cvs tag such as the one used above:
[root root]# su - service0 [service0 service0]$ cd /var/lib/aolserver/service0 [service0 service0]$ cvs up -r current [service0 service0]$ exit su - service0 cd /var/lib/aolserver/service0 cvs up -r current