Uyuni Documentation › Best Practices › PostgreSQL Database Migration

13 PostgreSQL Database Migration

13.1 New Uyuni Installations
13.2 Migrating an Existing Installation
13.3 Performing a Fast Migration
13.4 Typical Migration Sample Session

Uyuni 3 uses postgresql database version 9.4. Postgresql version 9.6 has been officially released for SUSE Linux Enterprise Server 12 SP3. In the near future postgresql 9.6 will become the base version provided by Uyuni. Currently version 9.4 is hardcoded into SUSE Manager, therefore when installing Uyuni it will explicitly use this version. This chapter provides guidance on migrating an existing 9.4 database to 9.6 on your Uyuni Server.

13.1 New Uyuni Installations #

Once support for postgresql version 9.6 has been officially released for SUSE Manager, no action will be required for new installations. The Uyuni extension will pick up the latest version during installation on SLES 12 SP3. This will be fully transparent to the user. Check the active postgresql version with the following command:

suse-manager-example-srv:~ # psql --version
psql (PostgreSQL) 9.6.3

13.2 Migrating an Existing Installation #

Before migrating to the new database version, ensure SUSE Manager is fully patched to the latest version. You can check if the system is ready to use postgresql 9.6 by issuing the following command:

suma-test-srv:~ # rpm -q smdba
smdba-1.5.8-0.2.3.1.x86_64

Important

Postgresql 9.6 requires smdba version 1.5.8 or higher

Warning

Always create a database backup before performing a migration

. The database migration begins by executing the following command:

$> /usr/lib/susemanager/bin/pg-migrate.sh

The pg-migrate.sh script will automatically perform the following operations:

Stop spacewalk services
Shut down the running database
Check if postgresql 9.6 is installed and install it if not already present
Switch from postgresql 9.4 to postgresql 9.6 as the new default
Initiates the database migration
Creates a postgresql configuration file tuned for use by SUSE Manager (The reason for the latest version of smdba)
Start both the database and spacewalk services

Note

Please note that during the migration the data directory of the database is copied for use by the postgresql 9.6. This results in temporarily doubling the amount of required disk space. In case of a failure, the migration script will attempt a restore to the original state. After a successful migration, you may safely delete the old database directory (renamed to /var/lib/pgsql/data-pg94) to reclaim lost disk space.

13.3 Performing a Fast Migration #

There are two negative aspects to performing a regular migration:

You temporarily need double the disk space under /var/lib/pgsql
Depending on the size of the database the migration can take up some time because the whole data directory needs to be copied.

It is possible however to perform a fast migration. In this case you do not need the additional disk space as the database files will not be copied but hard linked. This also has the natural effect of greatly increasing the speed of the migration process The entire migration could be completed in less than one minute.

Warning

Keep in mind if a fast migration fails, database restoration will only be possible with a database backup. Only perform a fast migration if you have an availabel database backup.

Perform a fast migration with the following command (Ensure you have a database backup):

$> /usr/lib/susemanager/bin/pg-migrate.sh fast

13.4 Typical Migration Sample Session #

A slow migration should provide you with the following output:

d235:~ # /usr/lib/susemanager/bin/pg-migrate.sh
15:58:00 Shut down spacewalk services...
Shutting down spacewalk services...
Done.
15:58:03 Checking postgresql version...
15:58:03 Installing postgresql 9.6...
Dienst 'SUSE_Linux_Enterprise_Server_12_SP2_x86_64' wird aktualisiert.
Dienst 'SUSE_Manager_Server_3.1_x86_64' wird aktualisiert.
Repository-Daten werden geladen...
Installierte Pakete werden gelesen...
Paketabhängigkeiten werden aufgelöst...

Die folgenden 3 NEUEN Pakete werden installiert:
postgresql96 postgresql96-contrib postgresql96-server

3 neue Pakete zu installieren.
Gesamtgröße des Downloads: 5,7 MiB. Bereits im Cache gespeichert: 0 B. Nach der Operation werden zusätzlich 25,3 MiB belegt.
Fortfahren? [j/n/...? zeigt alle Optionen] (j): j
Paket postgresql96-9.6.3-2.4.x86_64 abrufen (1/3), 1,3 MiB ( 5,1 MiB entpackt)
Abrufen: postgresql96-9.6.3-2.4.x86_64.rpm [fertig]
Paket postgresql96-server-9.6.3-2.4.x86_64 abrufen (2/3), 3,7 MiB ( 17,9 MiB entpackt)
Abrufen: postgresql96-server-9.6.3-2.4.x86_64.rpm [.fertig]
Paket postgresql96-contrib-9.6.3-2.4.x86_64 abrufen (3/3), 648,9 KiB ( 2,2 MiB entpackt)
Abrufen: postgresql96-contrib-9.6.3-2.4.x86_64.rpm [fertig]
Überprüfung auf Dateikonflikte läuft: [......fertig]
(1/3) Installieren: postgresql96-9.6.3-2.4.x86_64 [............fertig]
(2/3) Installieren: postgresql96-server-9.6.3-2.4.x86_64 [............fertig]
(3/3) Installieren: postgresql96-contrib-9.6.3-2.4.x86_64 [............fertig]
15:58:08 Ensure postgresql 9.6 is being used as default...
15:58:09 Successfully switched to new postgresql version 9.6.
15:58:09 Create new database directory...
15:58:09 Initialize new postgresql 9.6 database...
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locale "en_US.UTF-8".
The default database encoding has accordingly been set to "UTF8".
The default text search configuration will be set to "english".

Data page checksums are disabled.

fixing permissions on existing directory /var/lib/pgsql/data ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting dynamic shared memory implementation ... posix
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... ok
syncing data to disk ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the option -A, or
--auth-local and --auth-host, the next time you run initdb.

Success. You can now start the database server using:

pg_ctl -D /var/lib/pgsql/data -l logfile start

15:58:12 Successfully initialized new postgresql 9.6 database.
15:58:12 Upgrade database to new version postgresql 9.6...
Performing Consistency Checks
-----------------------------
Checking cluster versions ok
Checking database user is the install user ok
Checking database connection settings ok
Checking for prepared transactions ok
Checking for reg* system OID user data types ok
Checking for contrib/isn with bigint-passing mismatch ok
Checking for roles starting with 'pg_' ok
Creating dump of global objects ok
Creating dump of database schemas
postgres
susemanager
template1
ok
Checking for presence of required libraries ok
Checking database user is the install user ok
Checking for prepared transactions ok

If pg_upgrade fails after this point, you must re-initdb the
new cluster before continuing.

Performing Upgrade
------------------
Analyzing all rows in the new cluster ok
Freezing all rows on the new cluster ok
Deleting files from new pg_clog ok
Copying old pg_clog to new server ok
Setting next transaction ID and epoch for new cluster ok
Deleting files from new pg_multixact/offsets ok
Copying old pg_multixact/offsets to new server ok
Deleting files from new pg_multixact/members ok
Copying old pg_multixact/members to new server ok
Setting next multixact ID and offset for new cluster ok
Resetting WAL archives ok
Setting frozenxid and minmxid counters in new cluster ok
Restoring global objects in the new cluster ok
Restoring database schemas in the new cluster
postgres
susemanager
template1
ok
Copying user relation files
/var/lib/pgsql/data-pg94/base/12753/12710

[...]

/var/lib/pgsql/data-pg94/base/1/12574
ok
Setting next OID for new cluster ok
Sync data directory to disk ok
Creating script to analyze new cluster ok
Creating script to delete old cluster ok

Upgrade Complete
----------------
Optimizer statistics are not transferred by pg_upgrade so,
once you start the new server, consider running:
./analyze_new_cluster.sh

Running this script will delete the old cluster's data files:
./delete_old_cluster.sh
15:58:51 Successfully upgraded database to postgresql 9.6.
15:58:51 Tune new postgresql configuration...
INFO: Database configuration has been changed.
INFO: Wrote new general configuration. Backup as /var/lib/pgsql/data/postgresql.2017-07-26-15-58-51.conf
INFO: Wrote new client auth configuration. Backup as /var/lib/pgsql/data/pg_hba.2017-07-26-15-58-51.conf
INFO: Configuration has been changed, but your database is right now offline.
Database is offline
System check finished
15:58:51 Successfully tuned new postgresql configuration.
15:58:51 Starting spacewalk services...
Starting spacewalk services...
Done.

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