Tapes come up as "erased"

[ginie1227]

hi... i am on a mac- os 9.2.1 using retrospect 4.1i and we use the hewlett packard sure store tape 5000. we have used this same store tape drive since 1995 at our place of business. nothing has changed or moved. the problem is when i do a search for an old job that i want to retrieve, i put the tape in and it comes up "erased". i am kind of worried because i am not sure if the tape is really erased and how am i going to retrieve old jobs again. any help or info you can provide i would appreciate. thanks gina

[rhwalker]

There's no way I (or anyone else) can answer your question with complete certainty, but I'll try to give you some insight with our experience with our different drive / autoloader, an Exabyte (now Tandberg) VXA-2 1x10 1u PacketLoader (SCSI), under Retrospect 6.0 / 6.1, Mac OS X Server 10.4.11 and ATTO UL4D HBA in our Xserve.

 

In truth, there is no way for a program to tell whether a tape is truly "erased". When a tape is inserted, the drive tries to read the BOT header, which is used to encode such things as the tape name, the density, etc. If the drive reports an error at BOT, Retrospect thinks the tape is "erased". The solution, if your tape is still good (tapes do degrade with time), is to do a cleaning cycle with a cleaning tape and then re-insert the tape, see if you have better luck.

 

Now for a bit of a rant about what has, to me, been a dangerous bug in Retrospect for years, which I reported years ago under our service contract and which has never been addressed. This is actually a dangerous condition because of a bug in Retrospect for Macintosh that was fixed in the Retrospect for Windows version years ago (Retrospect Windows 6.5 build 319).

 

When Retrospect Mac needs new media, whether because a tape has filled up, or because a "new media" backup is being done, Retrospect will ignore the barcode labels in the autoloader and randomly choose from any "erased" tape in the autoloader, even if a barcoded tape for the correct desired member name, pre-erased and pre-named in Retrospect, already exists and is present in the autoloader. This means that an error at BOT for a tape with good backup data causes the tape to be believed to be an "erased" tape by Retrospect, and the tape can be overwritten.

 

This bug also makes it impossible to manage barcoded tape inventory, because you cannot simply fill the autoloader with barcoded erased tapes, pre-named as members to match the barcodes, and let Retrospect use the correct tapes when needed.

 

When I reported this bug back in 2005, Retrospect support declared that it was a "feature" and suggested that I file a "feature request" to get it fixed, even though this bug had already been fixed in the Windows version.

 

End of rant.

 

Retrospect 8 doesn't yet have the functionality or stability needed for our configuration, so I haven't been able to test Retrospect 8 on this point, but I believe that Retrospect 8 does not have this bug because Retrospect 8 is based on the Windows version of Retrospect, not the legacy code of the Macintosh version.

 

Moral of the story: make sure you write protect your tapes before putting them in the drive for a restore, and clean the heads on your tape drive often.

 

Russ

Edited June 24, 2009 by Guest