Hi One of our Physical Standby database aborted with "ORA-27061: waiting for async I/Os failed" error. The instance was killed by the DBWR process. Apparently, it was found to be an OS bug (IBM - AIX5L Based Systems) and an OS patch seems to resolve this issue. Our current OS Patch level is AIX5.3 TL5-CSP and we need to upgrade it to either AIX5.3 TL6 SP4 or AIX5.3 TL7 to avoid this problem occurring in the future. References:
Metalink Note Id: 467613.1 addresses this issue.
Happy reading :-)