I'm adding an extra chunk for mirroring my roodbs dbspace. The problem is that how can I know that the mirror dbspace is really synchronizing with the rootdbs?

from mirror concept , put in data in a time it go into 2 disks synchronously if you want to proof the mirror concept you have to delete the link that point to rootdbses' chunk if mirror bring up and system continue working , it's ok

After I've created the chunk, it has been tested ok. My point is that is there any command to see where the current chunk size is same with the mirror chunk to get accurate answer for syncronizing. I tried to use 'onstat -d' and 'onstat -D' but in -d I don't understand why the free in mirror chunk is zero. In -D I don't understand the 'page Rd and pageWr'. Pls Advice. THanks

Basically, the onstat -D shows how many pages had been written and read from that chunk since the database has been onlined. You can check the write number to see is there any increment. This way, for sure data is being updated.
I also use the onstat -Dr and using the grep command to get the only chunks I am looking at for my data performance.

Actually, I'm trying to write a script to compare the size of the main dbspaces cunk with mirror chunk so that i now that whether the mirror chunk really have whatever that is inside main dbspace. mybe an example like current main dbspace free size = 100000KB and mirror chunk free size = 90000KB. In this case, I will know that the mirror chunk is still have 10000KB to synchronize with main dbspace. That's why I'm trying to find out the command to check mirror chunk.