Thread: High Disk Utilization on Master with Streaming Replication Running 9.2.4
Hello,
What is the disk overhead for streaming replication? I have noticed that PostgreSQL’s disk utilization goes up by 3x on the master when a slave is connected. The setup only uses streaming replication, i.e. archive is off, there is no archive command. I see with iotop that the wal writer process is averaging 80% of IO. If I stop the slave, then IO utilization on the master drops to ~20%. Is there something that I am doing wrong? I have wal_keep_segments at 2048, checkpoint_segments at 96.
Thank you,
Joel
Re: High Disk Utilization on Master with Streaming Replication Running 9.2.4
From
John R Pierce
Date:
On 7/18/2014 4:44 PM, Joel Avni wrote: > Hello, > What is the disk overhead for streaming replication? I have noticed > that PostgreSQL’s disk utilization goes up by 3x on the master when a > slave is connected. The setup only uses streaming replication, i.e. > archive is off, there is no archive command. I see with iotop that the > wal writer process is averaging 80% of IO. If I stop the slave, then > IO utilization on the master drops to ~20%. Is there something that I > am doing wrong? I have wal_keep_segments at 2048, checkpoint_segments > at 96. > Thank you, > Joel there's bug fixes in 9.2 since .4 that could easily be causing what you're seeing. for instance, http://www.postgresql.org/docs/current/static/release-9-2-5.html (checkpoint memory leak when wal_level=hot_standby) 9.2.8 is out, 9.2.9 is coming out really soon. -- john r pierce 37N 122W somewhere on the middle of the left coast