rwk AT americom DOT com writes:

>I am trying to run amanda 2.4.2 on Linux RH8.0 using an Onstream ADR50
>drive.

I assume that you have the ADR50 SCSI drive. If you do, junk it.

Sorry, but that's about the only thing that I can tell you. The ADR50
SCSI versions have an OnStream confirmed firmware bug that makes it
impossible to use them with Amanda. End of Story.

The problem is the pause between writing the header and the data
blocks (or between data blocks). If this pause is longer than about
90-120 seconds, the drive will forget its position on the tape. On the
next write, your backup is toast. The resulting tape will either give
read errors which can be fixed by writing new data over it or will
even be unreadable forever (I nuked three tapes by doing so).

The scary thing is, that you won't notice this while writing. You will
notice it when you read data from the tape. Like in "I do need that
backup _now_". That's why I do run amverify after each backup to see
if I can actually read the data just written back in. Got burned and
learned this the hard way.

OnStream confirmed this a problem in their 2.39 firmware and told me
"we will fix this if we ever release a new firmware for the old ADR
drives (which they never did). Until then, please use the supplied
backup program".

If you're still willing to bet your data on such a drive, you can
configure Amanda to put all backups on the holding disk and then flush
them to the tape. By flushing you won't get any writing time gaps and
the backup will succeed.

Onstream Support will tell you that "this is a problem with your
OS". This is BS. I tested and confirmed the problems on three
different SCSI controllers and on three different OSes (FreeBSD,
Linux, Solaris 2.7).  Only after they couldn't point their finger at
anyone else any longer they admitted the firmware bug.

Once you get past the Support, you will find out, that OnStream
employs quite a few helpful and competent engineers. However, they
either consider their SCSI user base dead or simply can't fix this bug
because they don't have access to the firmware code any longer
(OnStream went bankrupt and the current, netherlands based Onstream
B.V. is another company that the OnStream that engineered the original
ADR50 SCSI tape drives).

Sell your drive to someone using a Windows Backup Program where it
works fine. Don't use it with Amanda.

The ADR2 tape drives (ADR60 and beyond) are fine. This is solely a
problem of the ADR50 SCSI drives.

        Regards
                Henning

-- 
Dipl.-Inf. (Univ.) Henning P. Schmiedehausen          INTERMETA GmbH
hps AT intermeta DOT de        +49 9131 50 654 0   http://www.intermeta.de/

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