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beton2

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NTBACKUP question

Hi,

I use HP DAT40i backup tape device, my server has 18 gb disc qouta for users, so full backups for now are about 9 gb. I do batch schedule scheme (winat + ntbackup).

I want to know:
- how can I check how free space remain on tape ?
- what to do if my backup is larger than free space, and I can't change tapes becouse it is at 2.00 am and I'm not available at my workplace becouse I slip at home...

Regards,
Robert
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Vick Vega
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I assume that you have a 12/24 tapes because you said you already backing up 9GB , when the DDS2 tapes are only 4/8GB.
Well anyway I will advise you to buy a backup program such as:
1.Veritas BackupExec
2.CA ARCserver
I personnaly prefer the first one because I think it's more friendly.
What kind a system you using?
Windows NT 4 ot Windows 2000?
1) you cannot check the remaining space on your tape.
One of the reasons you cannot is the way a DAT works. If the DAT detects a soft error on tape it will do a FastForward for a numbers off inches, and then tries again. This way you can be wasting lots off space on a tape that is near end of life. The second reason is that the compression factor constantly changes due to file type.
Databases can be compressed a lot, where .jpg and .zip cannot.
This also means that it is not likely (unless you have databases only) that you can use the full capacity that is stated by the manufacturer.
2) If you need to do a full backup in one run, a new backup application will not do you any good, you will need anoter streamer, or smart way's of backing up (incrementals, differentials).
The only thing the above apps have more than normal NTBackup (in this case) is the ability to look at multiple devices as it is one.
With NTBackup you have to create multiple jobs to manually spread the data among tapes, BackupExec can do that for you. NT backup does not know automatic tape spanning.

Hope this helps,
Greetings
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beton2

ASKER

Sorry for misunderstanding, I have new HP DAT40I with DDS4 support so I use 40 GB tapes (in fact 20 GB + hardware compression). I use NT 4 Server.

9 GB is size for normal weekend full backup. Daily backups are about 400 MB.
So if I have 10 tapes, and let's say one for one day of the week, I can receive 10 backups per tape - it works for 100 days. I can always buy a new 40GB tape and use it for some time till it will be full.

But the question is: "How can I check when it be full ? In others words: how much free space is still available on the tape ? (I can always estimate for how many days such tape will be enough).

Can I check it with ntbackup only ?

I was thinking about 3rd party software but for now I'm sceptic for many reasons (I check one of them, found in the package):
- tapes have incompatibile formats, so ntbackups can't read such backups,
- version of software I check can't do backups from network share, which is some kind important to me. I assume that 3rd party software cost much more than ntbackup which is included in system, and I'm afraid that they count even more for amount of every computer access licence.
- ntbackup and winat is this what I know well. I don't need software for its new, strange for first sight, windows interface, I want simple batch scheduling to automate my job, nothing more, nothing less.

regards,
Robert
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ASKER

Hi again,

I did not know your comment wlaarhov when I wrote mine. It has sense.

Ok, I will "create multiple jobs to manually spread the data among tapes" but what to do if I still exceed size of the tape with such relatively small backup job and ntbackup is operating in noninteractive style and there is no way to change tape at this moment. Next day morning I look at the log and see error at the end of it. I run ntbackup in interactive mode, want to check what is on the tape, but I can't catalog tape because ntbackup ask for tape #2 which is not exist. I waste all my previous backup on this tape, or at least way to access them, which is in fact the same disaster.

What is the solution for this scenario ?

Robert
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wlaarhov
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ASKER

This exactly was I want to know.

thx,
Robert