WAL级别不足以进行在线备份

Question

I have tried to do database replication in linux 7.0 red hat using postgresql.

I refered this URL for Confuring http://blog.terminal.com/postgresql-replication-and-backup-methods/ I completed the the steps upto this step

5. Configuring the slave server

but the step

6. Initial replication

when I executed this command in Master

-bash-4.2$ psql -c "select pg_start_backup('initial_backup');"

I got Error Like this

ERROR:  WAL level not sufficient for making an online backup
HINT:  wal_level must be set to "archive" or "hot_standby" at server start.

So kindly let me know where we are wrong.

Answer 1

On your master PostgreSQL server's configuration file <PG_DATA>/postgresql.conf there is parameter called wal_level it should be set to either "archive" or "hot_standby"

Both said to postgres to keep WAL segmetnts for replication server. The difference between the two is rather simple:

• "hot_standby" means that your replication server will allow connections for SELECT statements

• "archive" means you don't want that possibility.

More to read in this tutorial on streaming replication Also keep in mind that change of wal_level property needs server restart to take an effect.