I have a file share on my drobo where everyone has full access to it.
When I try to clear or set the archive bit using Windows explorer or the ATTRIB dos command it has no effect. The command does not get an error. It just won’t change the flag.
I can copy or delete files no problem. I also can
I am on the latest version of firmware.
This is really messing up my backup plan.
Any suggestions?
I’m afraid our NAS Drobos don’t support using the archive bit. One way around this is to use a backup program that compares by the time stamp.
How is this possible? This seems totally crazy to me.
what backup programs use the date/time comparison?
I’ve invested a lot of money in these things and I can backup with them.
I’ve verified with our engineering team that the Drobo Share and Drobo FS don’t have support for the archive bit but the 5N does. Here is our KB article regarding backup programs that will work with the Drobo FS:
Drobo NAS devices (and their competitors QNAP and Synology) don’t natively use NTFS. The filesystem is shared via “Samba” which is Windows-sharing software for Linux. I haven’t tried to set Archive bit over Samba, but it wouldn’t surprise me if that didn’t translate.
I use rsync and CrashPlan to back up my Windows computers. I use various other tools to back up other OS’s. In years past, I used Retrospect and briefly Windows Backup.
CrashPlan maintains a list of files which were already backed up, and their hash. If a file is already on the list, and its size and timestamp hasn’t changed, then it skips it. Otherwise, it backs up the file. Once in a while (I configured this for 28 days), it checks the hash of every file and compares with what’s in the backup archive.
Retrospect looks for changes pretty much the same way as CrashPlan does.
SuperDuper! copies entire disks. It checks every file, every time. That’s slow, but effective.
Unison is a file synchronization tool, not really a backup program. It maintains a list of every file and its hash, and compares both sets of files against that list, then flags anything that changed and either copies it or prompts the user to make a decision.
rsync is another file sync tool. It defaults to checking just filesize and timestamp (mtime), but can calculate file hash if you wish.
UNIX dump just copies everything that was created or modified (mtime) since the last backup. You can set a “nobackup” flag on files to exclude them from being backed up.
tar is even more stupid than dump.
Windows Backup and PKZip are the only backup tool I can think of which rely on the Archive bit to know what to back up. I guess it works, and it might be a little better than checking merely the timestamp, but it’s still easily fooled – and in any case, that doesn’t know anything about what you actually have backed up. I consider Windows Backup too brittle and vulnerable to bit-rot to recommend.
I suggest you look at other backup software. This is a regular topic of conversation in these forums. You could do worse than to read http://www.drobospace.com/forums/showthread.php?tid=76461
[edit: Darn it, Sky posted before I finished. That’s just unfair! Thanks for giving technical info about the Archive bit.] 
hi jimer,
have you had a look at the windows tool called Syncback?
theres a few versions of it around, one is free and others do a lot of things but ive bene using it with my drobo gen1 to gen2 mirrorring and its very very good. (syncback se)
have a look as it might be able to do what you’re after… just make sure you know how to use it before you set something up to play safe etc…