Updating catalog problems

[marki]

I have two backup catalogs for two separate DVD data sets that I use for archiving old jobs with several hundred discs in each. One of the catalogs can no longer be opened by Retrospect. I pulled an older copy from Time Machine and went into repair disk and chose to update. Everything was working fine until I got to a DVD that won't finish updating. I clicked stop and chose revert, so that it would start over on the problem disc if needed. Retrospect requested the next disc and continued on the process. This problem appears to be occuring quite frequently (almost every other disc) as I continue to update the catalog. Occasionally, I'll get stuck in a loop where Retrospect won't advance to the next disc even if I let it run overnight. I find myself having to click stop and then save, to force Retrospect to advance me to the next disc. I'm afraid things are not working properyly and I may be losing data. Is this normal?

 

Secondarily, I've thought of moving this system to a Drobo, but I am afraid of what will happen when I run out of space while using the largest available drives in all the bays. If I pull all four drives out and replace them with four new drives, will Retrospect continue to recognize the old set of drives correctly as I hot swam them. What has been your experience? Is retrospect the best software to archive old jobs?