Are non-concurrent differential backups possible?

[JOliver]

I am using Arcserve IT 6.61 on NT SP6a
Single server / single backup unit
(current: DDS4, soon: DLTIV)

Would like to be able to do a differential MONTHLY backup in addition to daily full backups.

My understanding is that differential is based on the archive bit set during a full backup. I am hoping that Arcserve can do this by verifying the DB and appending to the tape changed data.

A large % of our data is graphical (minimal compression) and doesn't change that much. Therefore I would like to append changes to the full backup at less frequent intervals.

Can anyone advise if a non-concurrent differential backup is possible OR an alternative method to do this.

Thanks.

 

[HeleneP]

I'm not sure exactly what yyou're trying to do but in the backup screen in arcerve under the schedule tab -> custom schedule there are 4 options for backup. 2 for full backup, 1 incremental and 1 differential. As long as your backups previous full backup was completed with teh backup method Full= Keep Archive Bit then you will be able to complete a differential backup next time.

 

[JOliver]

Thanks for your comments HeleneP.

I guess I wasn't to clear with my requirement.

I do a full backup nightly (excluding some large, relatively static folders). In addition to this I would like to maintain an end of month snapshot. I had in mind doing a full backup of all folders on 31st Jan, doing a daily backup of selected folders 1st-27th Feb, doing a differential backup 28th Feb (where the difference is between the 31st Jan and 28th Feb).

Perhaps it is possible to to do the 1st-27th Feb backups without clearing the archive bit, so that the 28th Feb differential backup would represent all files changed since 31st Jan? Can anyone suggest a problem with this?

 

[HeleneP]

Seems OK to me.

If you want to backup all files that have changed since your full backup on 31st as a differential at the end of the next month, then not selecting the archive bit for all backups in between the full backup WITH archive bit and the differential will do it.

It does seem and odd way to backup your data though.

Good Luck.