DISK INITIALIZATION ABORTED: potential instance overwrite detected

Technote (troubleshooting)


Problem(Abstract)

After running oninit -i, IBM Informix Dynamic Server fails to come online and writes the following messages to the message log:

16:06:00 DISK INITIALIZATION ABORTED: potential instance overwrite detected.
To disable this check, set FULL_DISK_INIT to 1 in your config file and retry.

16:06:00 oninit: Fatal error in shared memory initialization

16:06:00 IBM Informix Dynamic Server Stopped.

16:06:00 mt_shm_remove: WARNING: may not have removed all/correct segments

Cause

This is expected behavior. It is a feature first put into 11.70.xC1 that prevents the accidental overwrite of an instance which can happen when using the -i (full disk initialization) option. This feature utilizes the onconfig config file parameter FULL_DISK_INIT.

By default, FULL_DISK_INIT is set to 0. This setting protects the ROOTPATH file/device from being overwritten by oninit -i. A value of 1 allows oninit -i to perform full disk initialization (destructive overwrite) of the ROOTPATH file/device.


Resolving the problem

If it is desired to overwrite the ROOTPATH file/device and perform full disk initialization (destructive overwrite), as per the error message above, set the onconfig config file parameter FULL_DISK_INIT to 1 and run oninit -i.


As the server is initializing the instance and the ROOTPATH disk/file, you will see the following messages in the message log:

16:09:48 Value of FULL_DISK_INIT has been changed to 0.
16:11:17 IBM Informix Dynamic Server Initialized -- Complete Disk Initialized.

The first message indicates that the instance is setting the value of FULL_DISK_INIT back to 0 to as a defensive mechanism to prevent a subsequent oninit -i from performing full disk initialization (destructive overwrite). The second message indicates that the instance processes, threads, shared memory segments, memory structures and full disk initialization (destructive overwrite) has completed.


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Document information


More support for:

Informix Servers

Software version:

11.7, 12.1

Operating system(s):

AIX, HP-UX, Linux, Mac OS X, Solaris, Windows

Reference #:

1646549

Modified date:

2013-08-10

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