differential backup option

[element19]

i have a dds3 autoloader with 12/24 gb tapes. I realized that dds3 has tape capacities of only up to 12/24 gb. I am not able to backup my 4 servers on one tape even when compressed. Therefore my only best option would be to do a differential backup. The problem is that in differential backup, i would still have to do a full backup plus the differential. Will the option below work?

I will perform a full backup on sat of 2 servers
and a full backup on sun of the other 2 servers.
Then on Monday thru Friday i will do a differential backup of all four servers.

Thanks for your help.

 

[SQLBill]

Why are you trying to put everything on one tape?

Create different media sets and assign tapes to those sets. For example:

Media Set 1: 2 tapes: Full backups of server 1 and 2
Media Set 2: 2 tapes: Full backups of server 3 and 4
Media Set 3: 8 tapes: all differential backups

-SQLBill

 

[element19]

I'm not sure i understand about the media sets. I have 4 magazine each containing seven media cartridge. (one magazine per week). I am working from a remote site and go to the office to change the magazine once a week. So in that one magazine i would do a full backup of 2 servers on one cartridge (sat) and another full backup of the other 2 servers on another cartridge (sun). That leaves me with 5 cartridges in the magazine(mon-fri)to do a differential backup. Am i doing this wrong?

 

[SQLBill]

Nope, if you are changing out the tapes weekly that's different than having all the tapes in the library at one time.

-SQLBill

 

[element19]

Since the differential backup tape from m-f will backup all four servers, i'm wondering about the restore process.
If lets say my accounting server goes down and the full backup was backed up on the sat cartridge. Is it true that i would have to just restore with the sat tape and one of the differential tapes. Because the differential tapes backs up all four servers, i would just have to select the restore cartridge from either sat or sun from which the full backup was done, right?

Thanks again in advance

 

[SQLBill]

You would go to the RESTORE tab, find the most recent FULL BACKUP and the most recent DIFFERENTIAL for that server (which would require you to expand the restore file until you found the actual backup file you wanted to restore). Check both of those and restore them.

-SQLBill

 

[jdrourke]

SQLBill is right. You go to the last full backup and then hit it with the differentials to the point that it failed. You have to remember that the differential will only backup and restore data that has a date stamp more recent than the data that was existing from either the last full or differential backup.

 

[element19]

I've just ran into a problem with my full backup. The most recent full backup failed.
Will the differential backup continue the backup from the last successful backup or from the most recent backup even if it was unsuccessful?

Also, i'm doing full backups to disk-on my hd (sat & sun)just in case situations like this happens. Is this going to confuse the differential backup tapes. When i do a restore, am i able to restore from either the tape or disk backup or do i have to use the full backup that was backed up last?