You want to turn on the mirroring after it has been disabled. You edited the ONCONFIG file and set MIRROR parameter to 1. Similarly, set the MIRRORPATH parameter also. Informix server failed to come online after these configuration changes.
An assert failure similar to following reported in the online.log during startup:
11:11:26 Assert Warning: chunk failed sanity check
11:11:26 IBM Informix Dynamic Server Version 11.50.FC9W3
11:11:26 Who: Session(1, informix@abc, 0, 700000010388028)
Thread(7, main_loop(), 700000010346028, 8)
File: rspartn.c Line: 9500
11:11:26 Results: Chunk 1 is being taken OFFLINE.
11:11:26 Action: For all spaces other than temporary dbspaces, restore the
space containing the chunk from the archive. If this chunk
belongs to a emporary dbspace and if it is not the only chunk in
that dbspace, then drop and re-create the chunk. Otherwise drop
and re-create the temporary dbspace.
11:11:26 stack trace for pid 487632 written to /tmp/af.3ef1d3d
11:11:26 See Also: /tmp/af.3ef1d3d
11:11:26 chunk failed sanity check
11:11:27 I/O error, Mirror Chunk '/data/rootdbs.m' -- Offline (sanity)
The MIRRORPATH parameter is set.
Resolving the problem
You need to follow the steps below to start mirroring data on a database server that is not running with the mirroring function enabled.
1. Take the database server offline and enable mirroring by changing the MIRROR configuration parameter to 1. Leave MIRRORPATH configuration parameter blank.
2. Bring the database server back online.
3. Allocate disk space for the mirror chunks. You can allocate this disk space at any time, as long as the disk space is available when you specify mirror chunks in the next step. The mirror chunks must be on a different disk than the corresponding primary chunks.
4. Use the 'onspaces -m' option to start mirroring for a dbspace, blobspace, or sbspace. Start with the root dbspace first. Once this command is successfully executed, the server will set the MIRRORPATH value automatically.