[H-GEN] DVD+RW media for backups

[Greg Black]

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On 2003-11-17, Jason Parker-Burlingham wrote:
> Greg Black <gjb at gbch.net> writes:
> > On 2003-11-16, Jason Parker-Burlingham wrote:
> >> I've come into possession of a DVD+RW drive [...]  I've
> >> been playing with it trying to come up with a cheap, simple and above
> >> all reliable way to make backups of my system.
> >
> > So far, all I can think of is "Ick!"  Just yesterday, I spent an
> > hour on the phone with my sister talking her and her partner out
> > of such a scheme for their home network, which is quite similar
> > (although they have less data to backup, being writers).
> 
> I know.  I'd like to have a tape unit.  I really would.  However, this
> is what's in my price range right now and it also happens to
> correspond pretty well to the level of risk I want cover myself for.

I understand that price can be an issue, although I find it less
than compelling given the current prices of DDS-3 drives and
media.  Given the importance to me of my backups, I'd sell my
car and buy a tape drive and a cheaper car if that was the only
way out.

As for the level of risk, only you can determine that -- but I
hope to convince you that the media you plan to use may well not
provide what you think.

> > So I use hardware that's well away from leading edge (but still
> > nicely current) and I use the software that I developed over some
> > years and which hasn't changed for at least fifteen years.
> 
> Nice.  How many lines of code?

Six shell scripts totalling 1486 lines (of which 915 are code);
one (rarely-used) C program of 75 lines of code; three man pages
with 560 lines (in source form).

> > There's no way it can transfer to DVD or the
> > like.  And, while DVD is so limited in space, it offers no real
> > benefit over DDS-3 tapes.
> 
> The space limitations are the only thing *right now* that will make me
> try to take this thing back for a refund or whatever.  (Did I mention
> I was on the job a few weeks ago and discovered the horror of a
> customer whose tape drive had pulled the end of the tape right off the
> spool?  On all their tapes?[1])

This is common on poorly-maintained tape drives which don't use
tapes that are fixed to the spool.  Normal tape handling methods
will identify this as it happens and arrange for cleaning of the
EOT detectors.

> > I've acquired quite a lot of
> > software on DVD from various sources over the past year and have
> > regular issues with read failures.
> 
> On the other hand we have some guy---I think he has something to do
> with informationweek?---who very recently tested all his old CDs and
> found the only ones that didn't read well were those with stuck-on
> labels.  My experience matches pretty well, and I have no problem with
> churning through media often enough to reduce the chance of being
> caught out.

Well, my problems have been with DVD's, not CD's.  Specifically,
brand new distribution DVD's in brand new DVD-ROM drives.  I
don't get many errors and would never have noticed them if I had
not had a reason to copy the entire contents of several DVD's to
disk and found just enough errors that would have made me tear
out what's left of my hair had these been backups.

And, just for interest, the latest SAGE News Summary (Volume 2,
Number 39 of November 17, 2003) just arrived and has this item:

    ####### Technology: Time to Check Your CDRs

    Fred Langa (of InformationWeek) and his readers have been
    wondering if their old CDs that they have burned are still
    good.  This was sparked by a recent series of tests in the
    Dutch "PC-Active" magazine which suggest that CDs may fail
    in as little as two years.  Fred investigated all of his old
    backups that he had on CD.  In Fred's case, he found out
    that those CDs onto which he had glued a label were all
    unreadable.  Fred also refers to an earlier article of his
    (~2 years earlier) in which he talks about different dyes
    used in CDRs.  In that case he says that cheaper CDs (bluish
    or blue-green) wouldn't be as good a choice as more
    expensive (golden or greenish-gold).

    http://tinyurl.com/tesj
    http://tinyurl.com/hrpk

I replaced the long URL's with nice ones from tinyurl.com so I
could keep line lengths down.  And, since I lifted a whole
paragraph from the SAGE News, I'll also show this stuff from the
bottom of it:

    ------------------------------------------------------------
    SAGE News Summary Copyright (c) 2003, SAGE, The System
    Administrators Guild.  Please encourage others to subscribe
    instead of redistributing.
    ------------------------------------------------------------
    The SAGE News Summary is created and distributed free of
    charge by SAGE, The System Administrators Guild.  To
    subscribe or unsubscribe, send a line like this to
    majordomo at sage.org:
        subscribe sage-news

> > For now, my suggestion is: just say no.
> 
> Sadly, that's pretty much the one thing I can't do.  I'd *like* to use
> tapes.  I really would.  But I think that is going to be six or twelve
> months down the track.

Well, I hope I've encouraged you to re-consider optical rotating
media in the light of reliability concerns; and to re-consider
tapes in the light of the true value of backups versus the cost.

But, as always, this is an individual decision.  I was sure more
people would weigh in and I don't plan to say a lot more about
this.  However, I do think that everybody needs to consider the
question of backups very carefully -- unless you're really just
a hobbyist and don't actually store anything important on your
computers, in which case any kind of backups are probably just a
waste of time and money.

The thing about backups is that, like insurance, they are just a
drain on your resources -- unless you need them.  Unlike normal
insurance, which can only provide money and cannot replace your
documents, mementoes, and other real valuables, backups have
real value -- they really can give you back exactly what you
lost, but only if your backup regime is effective and your media
are reliable.

Cheers, Greg

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