概念

Write Ahead Log

• Why? Write Ahead Log 减少磁盘IO 做PITR
• Location: $PGDATA/pg_xlog
• Size: 16MB determinated at compile time
• rotation

check_point

''' checkpoint_segments = 3 # default checkpoint_timeout = 5 # minute default checkpoint_completion_target = '''

PITR & Logging Ship (warming standby)

• 参数 master postgresql.conf

#------------------------------------------------------------------------------
# LOG SHIPPING REPLICATION OPTIONS
#------------------------------------------------------------------------------
archive_mode = on # ArchPG
archive_command = '/usr/bin/omnipitr-archive -l /var/log/qfare_omnipitr/omnipitr-^Y^m^d.log -s /var/run/qfare_omnipitr
-dr gzip=rsync://l-interdb3.f.cn1.qunar.com/slave_PITR/ -dr gzip=rsync://l-interdb7.f.cn1.qunar.com/slave_PITR/ -dr gzip=rsync://l-interdb4.f.cn1.qunar.com/slave_PITR/ -db /var/run/qfare_omnipitr/dstbackup --pid-file /var/run/qfare_omnipitr/omnipitr.pid -v "%p"'
archive_timeout

• 如果一个从挂了，会是什么状况

Streaming (Hot Standby)

• Hot Standby Configuration

wal_keep_segments =   # This sets only the minimum number of segments retained in pg_xlog,  the system might need to retain more segments for WAL archival or to recover from a checkpoint

Time Line

• 什么是Time Line
• 通过 pg_controldata 查看 time line

配置文件

postgresql.conf

recovery.conf

方案

Streaming vs Logging ship

• Why This?

结构

工具

Omnipitr

• Binary Replication Tools

集群配置工具 LXX的

关键参数

• full_page

监控

• Streaming Process & Reciving Process
• RealTime Data Write

流程

• 打包

可能遇到的问题

streaming链接未建立

omnipitr出错

无法链接从库

锁

其他