What is the actual process of a Long Erase?

[borse2008]

Hello all, 

I know the process of what a long erase is what it does but from the user inserting the tape into the unit, what is the actual physical actions the drive and the tape drive does to each other?

Does it write or clean the tape or does anything to its heads?

Thats the type of answer im looking for.

Many Thanks Arron

[Colin_Weaver]

Both long and short erases mount the tape and perform a write operation

A short erase only resets the header information by writing an almost empty header (in theory a data recovery company could still get non-encrypted data back from this tape)

A long erase writes null data over the whole tape (hence it takes a long time) but should ensure your data cannot be recovered if that is your intention. Long erase is typically only needed where you have data security concerns around how your erased tapes will be handled.

Both erases in effect increase you drive use count by 1 and therefore affect any calculations on when you should run cleaning.

Neither type specifically cleans the drive heads, although it is possible that the long erase also has the effect of retensioning the tape as it rewinds it in one go at the end

[Marianne]

Have a look at this discussion:

https://www-secure.symantec.com/connect/forums/how-erase-data-tape-using-backup-exec-2012

[borse2008]

Colin, thanks for the quick reply, i actually now have another question in relation to this.

If you had problems with a tape in terms of its being ejected automatically even if the job hasn’t specified this, would it be looking for a tape with more room?  Or looking for a specific tape?

Colin i probably should log a new thread for this.  Would you ever use long erase in another way?

In terms of a suspect new set of tapes may of been used in an old Tandberg drive that could of been faulty and the heads may of written in a hard write/read error way.  Ive had at another site a customer with a new set of tapes and new drive with all updates done was still failing when backing up halfway through.  Once i did a long erase on this tape it completed successfully the following day. So im now doing a long erase on each tape before the scheduled backup is being run. Just for this week.

Thanks Arron

[Colin_Weaver]

You almost certainly need a new thread to explain exactly what you are trying to do - however the key point for tape use that often causes issues is that if a tape fills up mid job - we cannot start writing to the start of the same tape as when an overwrite occurs it in effect empties that tape it does not just get rid of the earliest set in the tape. When a tape fills mid job in a stand alone drive we then have no choice but to eject the tape and ask for a different one. In a library we would try and use a tape from a different slot.

If your media set settings are also wrong (too long for Overwriite protection or too short for Append) then this can have the same effect directly at the start of the job as the tape won't be useable when the job starts and is imediately ejected to ask for a suitable tape to be inserted.