Restoring from filesystem backup

Hello to everybody.

I just have a couple of newbie questions. I'm trying to restore our
databases from a file system backup. The backups are done with
rsync, the postgresql service is stopped before backups are done on
the server. The system is Fedora Core 4 with Postgresql 8.0.3.

Now back to restoring. I tried the following on a development box :)
1. stop postgresql service
2. mv /home/postgres/data /home/postgres/data.old
3. rsync over desired data/ folder from an external drive
4. start postgresql service
The last step failed with this error from the logs:
postmaster: could not find the database system
Expected to find it in the directory "/home/postgres/data", but
could not open file "/home/postgres/data/global/pg_control":
No such file or directory
Sure enough pg_control data was missing, actually /home/postgres/
data/global was empty. So I removed the 'bad' data/ directory and
replaced it with a previous day's backup, and everything restored
nicely.

My questions are (1) what am I doing wrong that the filesystem
backups would sometimes have an empty /home/postgres/data/global
directory, thereby not permitting me to restore from it, and (2)
what is the preferred way to restore from a file system backup.

Any help, even a shove to the right direction, would be greatly
appreciated. Thank you and have a pleasant day.

Dianne

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TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match

I'm no expert, but I did just accomplish a restore from backup; so at
least I can help you with your second question.

pg_dump is the animal you'll want to use to create your backup. I use
it wrapped in a script that automatically timestamps and names the
output appropriately. Args looks like this:

pg_dump -Ft -b -v the_db_name > the_output_file.tar

pg_restore restores the database. i.e.:

pg_restore -d the_db_name the_output_file.tar

Hope this helps -
Scott

On Nov 10, 2005, at 2:41 PM, Dianne Yumul wrote:

Hello to everybody.

I just have a couple of newbie questions. I'm trying to restore our
databases from a file system backup. The backups are done with rsync,
the postgresql service is stopped before backups are done on the
server. The system is Fedora Core 4 with Postgresql 8.0.3.

Now back to restoring. I tried the following on a development box :)
1. stop postgresql service
2. mv /home/postgres/data /home/postgres/data.old
3. rsync over desired data/ folder from an external drive
4. start postgresql service
The last step failed with this error from the logs:
postmaster: could not find the database system
Expected to find it in the directory "/home/postgres/data", but
could not open file "/home/postgres/data/global/pg_control":
No such file or directory
Sure enough pg_control data was missing, actually
/home/postgres/data/global was empty. So I removed the 'bad' data/
directory and replaced it with a previous day's backup, and
everything restored nicely.

My questions are (1) what am I doing wrong that the filesystem
backups would sometimes have an empty /home/postgres/data/global
directory, thereby not permitting me to restore from it, and (2) what
is the preferred way to restore from a file system backup.

Any help, even a shove to the right direction, would be greatly
appreciated. Thank you and have a pleasant day.

Dianne

---------------------------(end of
broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match

---------------------------(end of
broadcast)---------------------------
TIP 3: Have you checked our extensive FAQ?

http://www.postgresql.org/docs/faq

My questions are (1) what am I doing wrong that the filesystem backups
would sometimes have an empty /home/postgres/data/global directory,
thereby not permitting me to restore from it, and (2) what is the
preferred way to restore from a file system backup.

does the global directory exist on the drive you are syncing from? If
so ...
then it's a problem with your rsync.

check the options you are using with the rsync command.
check the rsync configurations in /etc/rsyncd.conf on the drive.
what user are you running the rsync daemon, and rsync command as?

That should point you in the direction to solve your problem.

Andy