Postgres tuning

pgtuning

Set File system Read ahead to 4096

    blockdev --setra 4096 /dev/sda1

Filesystem tests run at 256, 4096 and 8192 each tested with
    
    bonnie++ -f -n 0 -c 4 -u root | bon_csv2html > ir-results-8192.html

Run /services/postgres-tuning/determine_postgres_memory.sh on machine (copy via SFTP)

Set /etc/sysctl.conf 

    kernel.shmmax=OUTPUT
    kernel.shmall=OUTPUT

    vm.swappiness = 0
    vm.overcommit_memory=2

Run 'sysctl -p' to apply new settings

Edit /etc/postgresql/9.0/main/postgresql.conf

    shared_buffers = 800MB
    log_line_prefix = '%t:%r:%u@%d:[%p] '
    maintenance_work_mem = 100MB

    work_mem = 25MB

    wal_buffers = 16MB

    checkpoint_segments = 32
    checkpoint_timeout = 10min
    checkpoint_completion_target = 0.9
    

Other Test Configurations

    Test postgresql.conf - checkpoint_completion_target = 0.5 to see if it is better for I/O

At move to 4GB

    Rerun determine_postgres_memory.sh and reset kernel settings after bumping to 4GB.
    Set maintenance_work_mem to 200MB