In this article, I’ll describe in what scenario we encountered this problem, and how we resolve it.
Issue:
In certain customer scenario, where there are two data protection sites, one is local site for local backup, another is DR site for disaster recovery. There separately is one Backup Exec(12.5) backup server in two site, local BE backup server backed up data to local backup-to-disk folder and then backup-to-disk folder is transferred to remote BE backup server through CPS as scheduled. In order to verify if data on DR site can be recovered, we inventoried and cataloged media from remote BE backup server, as a result, part of medias were cataloged successfully, and some failed with error “0xe0000904”. E.g. when cataloging a media labeled as B2D000023, catalog job failed with the following error message:
“0xe0000904 – An error occurred while retrieving catalog information”.
Cause Analysis:
Over time, a media might be in overwritable state and be overwritten by other backup job, in this case, if a backup job spans multiple medias to store data, that is the data associated with the backup job are stored across multiple medias, so then data from this backup job might be overwritten and incomplete, if you want to restore data of this backup job, you’ll fail to restore.
So what about catalog? Normally, while cataloging media, it will retrieve all relevant medias including all data of certain backup job, e.g. a backup job spans 3 medias, while cataloging one of media, it retrieves the rest 2 medias, and eventually it will list all data of this backup job, and you can restore them. But when the situation(as above stated, some of medias are overwritten by other backup job) happens, the catalog job fails to retrieve media.
In customer environment, all local medias are copied to remote Backup Exec server through CPS, and inventoried and cataloged there to try to restore data from remote site, not from local site.
Among these medias, part of them have been overwritten by new backup job, part of them are in overwritable state. So while cataloging media, the catalog job fails. Check the catalog job detail:
From the above picture, we can see while cataloging media labeled as B2D000023, it retrieves other medias B2D000024 and B2D000022, which indicates that for those data from certain one backup job spans B2D000023, B2D000024, B2D000022. But data on B2D000024 and B2D000022 have been overwritten, so can’t retrieve relevant data from them.
Solution:
Actually, the phenomenon (catalog errors) is normal. In this case, customer data is not lost, what we have to do is that to show customer the way we retrieve these data and explain why this happens. I provide a way to avoid the error and at the same time, can retrieve these data from remote site.
Steps:
1. From Tools->Catalog, please make sure that “Request all media in the sequence for catalog operations” is unchecked.
2. First of all, determine which media is overwritable, exclude these media while cataloging media, do this from local Backup Exec server console, as from remote BE, we can’t determine this. In this case, just B2D000014 is in overwritable state.
3. Second, determine the sequence of catalog, do catalog from the earliest time media. From remote Backup exec server, sort “Date modified” of media from windows explore. In this case, B2D000139 media has the earliest time. That is starting catalog from B2D000139.
4. At last, determine all medias are cataloged. From catalog job, we can see which medias are cataloged.
If any other medias are not cataloged excepting those medias shown on catalog job, repeat step 2 and 3 until all available medias are cataloged. In this case, it automatically catalogs all available medias(B2D000139 and B2D000798).
Now, after cataloging media successfully, you can restore them from remote site.
Any misunderstanding, welcome to correct.
Thanks
