Thanks Eric for the response. Actually I need a simple understanding. As much as it sounds stupid, I want to understand the workflow of Journal, WIJ and Database when we have a transaction.
My understanding is :

Transaction ----> Write deamon writes to WIJ ------> Write Deamon writes to Database--------> Journals are updated.
My Questions are:
1. What is the content of WIJ, these contains just pointers of data or actual data?
2. If Journals are written after data is committed to database then in case of application consistent snapshot creation, during iris freeze, database writes are suspended, so how the journal files are still getting generated. (I understand Write daemon does not play a role in Journal)

3. Suppose I have a time gap between IRIS freeze and snapshot generation and in between couple of journal files are generated. If I have snapshotted WIJ, Journal and database and on Secondary host  I want to  recover the latest data by applying from the updated journal, can we do that.

4. I am trying to snapshot WIJ, JNL and data and trying to start the instance in the secondary host by mapping the snapshots. But I am getting WIJ mismatch error following which Journal Recovery error. Why is that??

Thank you for providing your feedback

Thank you, Vitaliy, for sharing the useful links. They have been very helpful.

I would also like to confirm whether there are any cache-related settings in Red Hat 9.4 that could be contributing to the increased frequency of WIJ errors in my environment.

Thank you, William, for your response. It has provided significant clarity.

I am planning to perform an application-consistent snapshot, and it would be helpful if you could guide me through the exact recovery steps. This will allow me to identify any gaps in my process, as I am consistently encountering the WIJ mismatch error.

Thank you Julian for the response. 

After issuing "iris freeze <instance_name> , if I check iris stat <instance_name> and there I can check the parameter WDSUSPD=1, can it be also be a validation of IRIS instance freeze. 

because as soon as I am thawing the instance "WDSUSPD" in "iris stat" output changes back to 0.