Re: For the hardware guys...

[Bruce Smith <bruce@xxxxxxxxxxx>]

> >> $500-600 bucks for a new drive is way too expensive for me.
>
> >Then get an older DDS-1 or DDS-2 drive instead of the DDS-3.
> >The drives are more reasonably priced and the tapes are still cheap.
> >Besides, it's a much better drive IMO.
> 
> Exactly ,my ~$80 dollar DAT drive from Onsale only holds 2Gb but it's
> *FAST* and has been completely problem free.  And since my "/home"
> isn't bigger than 2Gb the capacity isn't a problem.  And the "newer"
> DAT drive I buy someday will be able to read the tapes from the old
> drive (not that I suspect the current drive will die anytime soon).
> DAT drives are fairly common so it's also a nice way to take HUGE files
> to/from the office (a 40Gb DAT drive that happily reads my tapes) or
> other places.  The cost of RW CD media has come down so the last point
> isn't as big a deal as it once was, but still 2Gb > 640M.

We have about a dozen HP DDS-1 and DDS-2 tapes at work that have 
been backing up almost 2GB each DAILY, some for over 10 YEARS.  
We've had very few failures over that time.  Very reliable.

It's also my understanding (IMNAHE - I am not a hardware expert :)
that DDS drives format the tape and verify as they write.
The drives automatically skip over bad spots on the tape.  
That's why the tape media is so much cheaper.  It doesn't have 
to be verified perfect and formatted before leaving the factory.

Also, if you purchase some commercial backup software (cheap for
Linux), the software indexes the tape making restores of single
files much faster, skipping right to the file on the tape.
Because of the design of the tape, I don't think that's possible
with TR-4 type tapes.

I've done some tests with the HPUX software, and on a full DDS
tape which takes about 1.5 - 2 hours to backup, I've never had it
take more than 5 minutes to find and start restoring a single file.
While testing, I've even tried rewinding, and restoring the very
last file written to the tape - less than 5 minutes before it 
starts restoring that file.  (the actual restore may take longer
if the file is really large, but it finds the file and _starts_
restoring in less than 5 minutes)

You can't do this with "tar" or any of the standard Linux backup 
programs that I know of, but I've heard it works with some of the 
commercial backups for Linux.  I've never tried it because I do 
very few restores and can't justify even a modest cost.

--------------------------------------------
Bruce Smith                bruce@armintl.com
System Administrator / Network Administrator
Armstrong International, Inc.
Three Rivers, Michigan  49093  USA
http://www.armstrong-intl.com/
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