Today,our monitor report a pg slave instance'disk space usage reach 96%，I login in to the machine，and find the pg_xlog dir take up more than 2TB，which is abnormal. the number of WAL file in the pg_xlog dir is more than 130k,while we set the wal keep number to 8192. I think there is something stop the replay,so I check the pg_stat_activity,pg_prepare_statement,pg_xact etc,but find all normal. I run： ps auxwww | grep postgres and can find the wal receiver and streaming receiver work happily，because the wal file name，the streaming log id changed.
So I have no idea. I then restart the slave PG,and find it recover from a very old wal which is one month ago. We are now set up a new slave for the master while let the recover from this slave go. the PG version is 9.1.9,OS is CentOS 6 x86-64. Jov blog: http:amutu.com/blog <http://amutu.com/blog>
