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Error encountered when opening files restored from Netware/DLT Drive

We have restored various files from a backup tape from a few years ago. The backup tape was created with a 40/80Gb Compaq DLT Tape drive. The Operating system in use at the time of the backup was Novell Netware 5.0. The backup software in use was Arcserve IT (version 6.0)

The files have been restored successfully to a Windows 2003 Server environment, however upon trying to open a variety of files, they do not successfuly open. Microsoft Excel files give an error message of "The File is not recognised". An attempt to open PDFs, JPGs result in errors as well. Word Documents result in Word prompting to decode the file from a list of languages.

A different backup tape from a similar period has also had files restored from it, resulting in the same error messages when trying to open the aforementioned restored files.

Can anyone shed some light as to what is happening, why it is happening and any possible solutions to retrieve the data

many thanks
Storage SoftwareNovell NetwareStorage

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8/22/2022 - Mon

I have never tried to restore from a Novell backup to a Windows backup.

I would have been pretty impressed if it did work without any issues.

Do you have an oppurtunity to restore a Novell environment?

to a Novell environment I meant to say
Bud Durland

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I agree with BudDurland, you probably have restored a NetWare compressed files.

Giovanni Coa
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James Murphy

If you try send us a single restored file I can check if it is NetWare compressed using our NetWare server.
How many MB or GB are you restoring ?

Hope this can help you,
Giovanni Coa

Yeah.  One of the "gotchas" that even NetWare shops run into - neglecting to set the backup to uncompress the files before backing them up.  The tape drive and/or backup software has its own compression that works quite nicely - backing up NetWare compressed files is just asking for problems because they need to be restored to the same version of NetWare, and often the same version AND support pack AND in-between patches (because the compression differs between versions of NetWare/NWFS/NSS).

Backup software (and Computer Associates and even Cheyenne if they still existed will tell you this) is not meant for platform migration.  It's meant to recover your data to your existing platform.  A backup of a NetWare filesystem holds things like extended attributes and namespaces and trustee information that doesn't translate to the Windows environment at all. so you're just lucky you were even able to trick it into restoring a NetWare backup to Windows in the first place.  

The only way to restore data from a  non-Windows platform to Windows is to use emulation when doing the backup, rather than doing a native backup.  For example, backing up Samba "shares" as though it were a Windows box, instead of doing a native Linux/*nix backup of it supported filesystems (ext2/3, ReiserFS, etc.) or backing up NetWare "shares' through NFAP/CIFS - or doing the backup through an authenticated NetWare client PC letting the redirector handle all the attribute translation and such - and in those cases, compression is moot, as all the files would be passed to the client doing the backup in uncompressed form.