Alan Brown wrote:
> On Thu, 12 Jun 2008, bjoern_busch wrote:
>   
>> How much would you pay for such a drive? Just a rough guess for my
>> orientation.
>>     
>
> That depends on how much storage you need.
>
> An external Quantum LTO2 drive can be had for about EUR 1000, these are
> 200Gb raw capacity and the tapes are ~ EUR 22 each.
>
> AIT drives start at about EUR 500 for external scsi units.
>   
>> And sure, data loss would be way more painful / expensive than a new drive,
>> but I think right now the tendency is towards cutting down the amount of
>> data that gets backed up all the time. A lot of stuff hasn't changed in a
>> while, so maybe we can get the regular backup size down to ~10GB. We don't
>> need to backup data all the time that hasn't changed since last year. or
>> longer.
>>     
>
> You do if you're using DDS. You can't 100% rely on just-recorded tapes
> being 100% readable and older tapes are susceptable to "bit-rot".

Nothing is ever 100%.

I've had reasonably good luck with HP branded DDS drives and Fuji or 
Sony branded DDS tapes. Granted, they are old technology and not up to 
current needs. But choice of brand is critical. Some others I tried in 
the past (or had foisted on me) were much less reliable.

One department I work for came up with money for a new AIT5 tape library 
a year and a half ago. I've been able to have smoothly running nightly 
backups with periodic archives and adequate redundancy to cover 
everything and have room for growth. I'm confident I can recover 
anything they need.

Another department I work for has been unable to scrape up any money for 
the backup system even though I've been pushing them and submitting 
proposals for 2 years. I can't run nightly backups, because it takes 
several days to get everything done using the existing DDS/3 drives, and 
even then, I have a fair number of partitions that run off the ends of 
tapes. What's the cost of data loss? I'm expecting them to learn that 
someday. When the department head, or some influential department 
member, loses an important document or data file that happened to be off 
the end of a tape, or that we didn't back up because it wasn't in the 
time window, then maybe the money will appear and I will be able to do 
proper backups for them. In the meantime, I have plenty of proposals and 
requests to point to if anyone ever complains that their data is not 
being backed up.



---------------

Chris Hoogendyk

-
   O__  ---- Systems Administrator
  c/ /'_ --- Biology & Geology Departments
 (*) \(*) -- 140 Morrill Science Center
~~~~~~~~~~ - University of Massachusetts, Amherst 

<hoogendyk AT bio.umass DOT edu>

--------------- 

Erdös 4



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