tape back up help

[hargi]

I need this to be as simple as posible as im leaving in the next few days and want to get ti sorted.

Using Suse and tar to disk.

On the server i have a folder that contains the last 10 days data in /backups/year/month/ then it has the zip files for each day in there.

If i write these to tape, on the tape it creates /backups/year/month/ list of files.
After i put the tape in the follow week with out rewinding what will happen
as will it create a new /backups/year/month list of files? so there will be 2 /backups/year/month on there with reoccuring dates so how would i go about restoring the correct files.

Or would it be better just to keep 5 days data on the server so that theres no duplication of data on the same tape. or should i rewind the tape at the start of each back up?

TIA

 

[memyselfandi]

I've not done this with tar under Suse, but have with other tools under other Unix flavours, but you can use the mt command to skip forward one file where the file in this case is the tar archive session ... hence ....

tar xvf /dev/st0 filename

would recover from the first set of files on the tape and

mt -f /dev/st0 fsf 1
tar xvf /dev/st0 filename

would recover from the second set, assuming the tape started the restore from a rewound state. See the man page for mt for details. Note that if you are using a single spindle cart (e.g. DLT based) then the very mechanism of ejecting will rewind the tape.

But I would not use the backup schema you are with multiple backups going to the same tapes just in case a rewind error causes data to be overwritten. With no info on what the requirements for data storage are its hard to suggest a schedule though.

Whatever you decide to do though you need to make sure that you can recover from the tape, (and in the original multiple backups per tape scenario that you can get the version back that you need).