Re: Cold backup using dd

>> From original note >>

I am attempting to come up with a solution for backup/recovery.(duh!) Wondering if anyone has had experience with Cold backups using dd? Can I write more than one disk to a tape?
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Yes, you can write more than one file to a tape using UNIX dd utility, but it is your responsibility to know what is on the tape and to make sure the data files do not exceed the capacity of the output tape.

Also be careful to not rewind the tape until all files that are going on the tape are in fact written to the tape.

I used dd to back up 12 gig of raw partation onto a tape rated for 5 gig using a tape drive with hardware compression. I learned to limit the input files to 10 gig for safety since over time the compression ratio on the OS files that make up an Oracle tablespace declines as data is added to tables/indexes. I gathered the tapes every day and wrapped them with the log of the backup job. They worked when we needed them.

System administration meanwhile had a rewind at the start on one of their scripts and when it executed midway through it overlaid part of the earlier backup. System Admin's like to pass out commands with things like rewind attached so unless you are a strong shell script writer you need to make sure that the commands or utilities you are using work the way you need.

Hope this helps. Received on Thu Jan 23 1997 - 00:00:00 CST