the best way to copy a 16 GB Oracledump to tape?

[Herr Ing. LITSCHAUER]

Hi all..

i have an 16 GB Oracledump file from an Export and i want to copy the dump to a dds4 data cartridge to send it to our customer.
i have tried it with dd to a LTO1(dd if=expZDB2002.dmp.Z of=/dev/rmt/LibK1d01 obs=8192) but the "restore" of the file takes to much time.
any suggestions??

thanks
Christian

[A. Clay Stephenson · Accepted solution]

Your blocksize is much too small (and yes, the Oracle block size is irrelevant). You need to increase the blocksize to something like 1000k and moreover specify only bs. Your 8k blocksize will not keep the device streaming. Your method also adds the unnecessary buffer copy.

dd if=/expZBB2002.dmp.Z bs=1000k of=/dev/rmt/xxx

The restore will still take some time but this should be noticably faster. Because the .Z file is already compressed; you should choose a non-compression tape device node if possible (or manually disable compression).

[Ivajlo Yanakiev]

I think that bs=2048k is nice

[Herr Ing. LITSCHAUER]

Hi...

thanks for your input.
i tried it with bs=4000k and without compression-->> the restore takes 1:48 hours.
i think this is ok. i will try a second time with bs=2048 to see the difference

regards
Christian

[Herr Ing. LITSCHAUER]

only for information:
the test with bs=2048k takes the same time as with bs=4000k

[Herr Ing. LITSCHAUER]

the restoretime of 16 GB from tape with dd and bs=2048k is ok