IGW020I

Explanation
The system detected that another system has issued
a R/W mount for a file system that is currently mounted on this system.
In
the message text:
dsname
The name of the HFS data set that has been mounted R/W elsewhere.
sysname1
The system name of the other system that mounted the file system.
date1/time1
The date and time that the other system did a R/W mount of the
HFS.
sysname2
The system name that this system expected to have ownership of
the HFS.
date2/time2
The date and time that this system expected to be the last file
read/write mount of the HFS.

System action
All file system operations are disabled except
for unmount.

Operator response
Contact the system programmer

System programmer response
Determine why an illegal R/W mount
was done on another system and take steps to prevent future occurrences.
 Putting both systems into the same GRS ring is the recommended prevention
mechanism. The file system can be reactivated by unmounting it and
then remounting it.

Source
HFS Sync Daemon