OT: redhat

[Bill Vermillion]

Shakespeare wrote plays and sonnets that will last an eternity, 
but on Tue, Nov 09 23:37 , D . Thomas Podnar wrote:" 

> On Tue, Nov 09, 2004 at 04:47:54PM -0500, Bill Vermillion wrote:
> > On or about Tue, Nov 09 12:25 , while attempting a Zarathustra 
> > emulation Jay R. Ashworth thus spake: 

> > If anyone is using QIC devices they can vary greatly.   You can
> > make up to about 30 passes on a tape when recording as you reverse
> > and go the other direction for each track, and then if you do
> > a complete verify that also adds up.

> > The old AT&T systems would default to >I think> 2000 passes per
> > tape.  These were smaller QICs and you would use at least 8 passes
> > on each backup, and then when you hit the preset limit you would
> > get a warning.  I believe the AIT also uses a warning, but I'm not
> > sure.

> > Perhaps Tom could let us know which emit the warnings.

> Always, tapes have been good for many thousands of passes,
> given that people were doing proper head cleanings, which would
> be recommended at about once per week for drives doing nightly
> full system backups.

I've noticed that the Sony series with the self-cleaning device in
the new models did help consierably.  

It seems no one ever looks at the blinking light on the DAT drives
that indicate it is time to insert a cleaning tape.

> Unfortunately, no one really maintains tape drives. I've had
> situations in support where we've asked people who've had a
> tape drive for 5 or 6 years when it was last cleaned.

>  "Cleaned? How do you do that?"

And the nice thing about BE and even LT is that when a verify files
there is a suggestion of using the cleaning tape.

And since it seems that few people pay attention to the messages
I have copies of those mailed to me.  Often their first hint
that anything is wrong is when they get a call from me.

> So conventional wisdom is to rotate tapes once every year (50 backups)
> or 2 (100 backups), AND clean them religiously.

> Fortunately, all modern tape drives support an
> industry-standard diagnostics mechanism called TapeAlert(tm),
> first pioneered by Hewlett Packard. Drives with TapeAlert
> support can diagnose themselves, their environment, and their
> media, and queue messages for software that is capable of
> asking for it.

> TapeAlert can alert the user to many problems, including tapes
> that have snapped, drives that need cleaning, termination or
> undervolt/overvolt conditions, or even media that is having
> correctible read or write errors but needs replaced, BEFORE
> any data is lost. We've even had a tape drive here report that
> it was about to fail, and tell us to stop using it.

Thankfully the only messages I've ever gotten were ones
that suggested cleaning.   When I don't get a message that's when
it usually a problem.

> BackupEDGE has been supporting TapeAlert diagnostics since 1998.
> Lesser products still ignore this capability, which boggles my mind.

That's why even though my customer base is dwindling rapidly
with the last two SCO being decommisioned now - I use BE on the
platforms that support it - and LT for platforms that BE doesnt
support such as the SGI's I used to admin and the FreeBSDs.


> Funny BackupEDGE support story...
> 
>   "There must be something wrong with BackupEDGE. I can't do backups
>    on Fridays?"
> 
>      "What happens on Fridays?"
> 
>   "Well, my consultant gave me a new batch of tapes, and said
>    'make sure you put THIS one in every Friday', so I do, but after
>    about 30 seconds it just pops back out!"
> 

> They never even looked at the label on the cartridge.

Thanks for the chuckle.

Bill
-- 
Bill Vermillion - bv @ wjv . com