How to copy a DDS3 to another DDS3

[Daniel Ubeda]

Hi,

I need to make a backup copy of DDS3 DAT.
I have not two drives in one server.
Are there any command like dd to remote copy this DATs ??

thanks

[Jeff Schussele]

Hi,

Well, I'd think dd would be the command of choice. I'd probably create an intermediate file, xfer it & write it back to tape on the destination - something like:

dd if=/dev/rmt/0mn of=/path/to/dir/file.name bs=64k
then ftp, rcp, scp, NFS, whatever it over to dest system - then write it to tape:
dd if=/path/to/dir/file.name of=/dev/rmt/0mn bs=64k

Don't need to make it any harder than it really is.

Rgds,
Jeff

[Jeff Schussele · Accepted solution]

Oh - OK, I think I understand now.
You just want to dupe a tape.
Same thing as I laid out - just skip the xfer section. Same thing - just create a file with dd & write the file back to a new tape with dd.
That's all there is to it.

Cheers,
Jeff

[A. Clay Stephenson]

It depends. If the backup was made with tar or cpio then you can dd to disk and then dd back to tape but if you used fbackup or OmniBack then variable blocksizes are used and dd won't do the job.

So, what kind of backup is it?

[Daniel Ubeda]

I have two tapes.

1.- DDS3 with tar, and I want to duplicate.
In this case, I have not two drives in the same server.

2.- DLT with OBII, and I want to duplicate.
In this case I have a Library with 2 drives and I can do a dd if=/dev/rmt/1m of=/dev/rmt/2m
you say that 2.- not work ok ?

[A. Clay Stephenson]

You can use dd on the tar and that will work just fine.

To copy to disk:

dd if=/dev/rmt/0m ibs=20b obs=200b of=/mydir/myfile.tar

To copy from disk back to tape:
dd if=/mydir/myfile.tar ibs=200b obs=20b of=/dev/rmt/0m

Man dd for details.

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OmniBack II and/or Data Protector tapes cannot be duplicated. The format is simply too complex. The only option is omnimcopy but that requires identical drive to identical drive although they could be on different hosts.