Re: Onstream ADR50 Block Size
2003-04-11 12:35:11
On Fri, Apr 11, 2003 at 09:01:33AM +0000, Henning P. Schmiedehausen wrote:
> 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
>
Henning,
that is a cogent description of the OnStream problem.
Would you consider going to amanda.org and adding it to the FOM?
--
Jon H. LaBadie jon AT jgcomp DOT com
JG Computing
4455 Province Line Road (609) 252-0159
Princeton, NJ 08540-4322 (609) 683-7220 (fax)
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