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Question about running two incremental backups in Symantec Backup Exec 2010

Hi All,

Using Symantec Backup Exec 2010 running two daily backups, "Backup A" is a daily incremental backup to a static USB hard drive which runs at 11pm weekday evenings. "Backup B" to a removable USB hard drive at 10am weekday mornings which is taken off site once offices close (serving as an off site backup). My question is this:

If Backup A runs on a Tuesday Night, completes successfully and resets the archive bit on all of the files it has backed up, then at 9am the next morning a user makes a change to a file which in turn will mark the file as "to be included in next incremental backup", then Backup B runs at 10am and includes the file that had changes made to it at 9am and proceeds to reset its archive bit, will Backup A no longer include the  file which was changes at 9am (I need it to be included in both backups using incremental not differential)? or does each backup job/task in Backup Exec have its own unique archive bit?

Unable to find information on how archive bit is handled when two different incremental daily jobs are run and would much appreciate any information anyone can provide.

Thanks in Advance,
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Another approach you could take is to use the Backup Exec "Off-site Copy" on your Backup A job.  You can set up two USB hard drives as Off-Site drives, and after it runs the backup job, it copies it to whichever off-site drive is connected.  Just swap the drives and take one home every day.
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Thanks ienaxxx for your opinion, however I was hoping for insight into how archive bit works, whether each job in backup exec has its own or whether there is a global one, and how the two backups handle a changed file (will Backup A still back the file up even though Backup B has backed it up already?).
There is a global one. it's a filesystem option.

So backup A will not backup the same files as B
And this is the reason i suggested you to use differential. :-)
@joshbula: thanks for the suggestion. Looking in to this now.

@ienaxxx: thanks for the clarification. Using differentials isn't something we're going to consider just yet, but I do appreciate that you've taken time to respond. Thanks again.
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What is your resistance to running a differential backup?

ienaxxx is correct that it's the only way to do what you want to do with standard tools (i.e., unless you want to write your own backup tools library).

If there's no way you're going to use differential backups, there is another way to do more-or-less what you want to do, and that is to use a backup application that can be run in incremental forever mode with synthetic full backups, and which allows you to replicate backup jobs offsite.

In this scenario, you run a full backup.  You run your periodic incremental backups for the rest of all time (or until you switch backup applications).  After each incremental, you replicate to a second site, ensuring protection in case of a site-wide disaster.  Since this is only an incremental backup, the amount of data you have to replicate will be relatively small, but make sure your bandwidth can support the transmission of the amount of data you expect to have in your replication window.

Now, the process of restoring from an incremental forever that spans years can be problematic, so periodically (once a week, once a month, your business processes decide), you'll want to create a synthetic full backup from that incremental forever store.  When doing this, the backup application creates a point-in-time full backup (preferably, on tape for longevity and to allow you to take it off-site) that is exactly the same as if you'd run a full backup when you ran your last incremental backup, so you no longer have that years' worth pool of incremental backups to restore from should you ever need to -- just one synthetic full (probably on tape) and whatever incremental backups happened after that (which will be on disk, so easy and quick for the backup application to do).

HP's Data Protector can do this.  I believe CommVault Simpana can as well.  I don't know if Backup Exec can do it.
Reviewed backup options and opted for Differential in the end. Thank you for the in-depth description of using synthetic full back-ups SelfGovern.