[Leica] Tape back up for photographers

[dennis at hale-pohaku.com (Dennis)]

Hi Spencer,

I think we may want to put this over to the Imagestore list, but.

At some point, say over 10TB, and growing, I think you are reaching a 
point of diminishing returns using disc drives for backup and/or 
archiving. Managing a lot of disc drives manually becomes a tedious and 
error prone task. This is where automation can be your friend. John's 
tape library is more than I would expect a photographer to need but I 
would want a library that accepts at least two drives in order to 
migrate data to the next generation media. Typically these libraries are 
attached to servers. I am not sure but expect that you can run them on a 
unix or windows system, not sure about Mac.

It's likely that you will need a server to keep up with the performance 
of the drive. LTO 4 can write data at speed of up to 120 MB/s.I  don't 
think windows desktop can serve up that data rate. The drive can stream 
at lower data rates but obviously the backup will take longer.

The LTO format is very reliable. They are not designed to be consumer 
products, the typical customer is going to be a large corporation that 
expects and gets a reliable product. The media life that John quoted 
sounds like the spec to me. Once you write data to the tape you should 
never have to check it. If you want I can discuss the read after write 
that occurs in real time when data is written, the error correction that 
is part of the LTO specification, and, importantly the servo tracking 
that is important to ensuring data written can be read back on another 
drive. Keep in mind that the major drive manufactures are HP, IBM, and 
Quantum (Quantum acquired its seat as one of the technology providers of 
the LTO Consortium when Quantum bought Certance, a spin off from Seagate)

Backup software is going to be selected from the library vendors list of 
qualified vendors.

Goodnight,
Dennis


Spencer Cheng wrote:
> John, (& Dennis),
>
> Suppose you are a working pro like Tina, Leo or Ted, or..., and you have a 
> gazillion digital photos, what would you buy for tape backups? Assume that 
> it has to work with a PC and a Mac, though not at the same time.
>
> How reliable are these tapes? How frequently do they have to be replaced? 
> How often do the content have to checked? What S/W should they use? Is 
> there a recommended backup schedule?
>
> I've came across cases where the tape drive was flakey and the tape was 
> blank. I also seen tape drive s/w that generates hundreds of (transient?) 
> errors when I worked for a small company and we used tapes for backups.
>
> More fodder for the wiki but I think this is useful information to capture 
> because once one data needs exceed 2TB, commodity NASes becomes a bit of a 
> dead end. Even my home brew NAS becomes less useful once it gets to >3TB. 
> Having a stack of NASes is no better than a stack of external disks (or a 
> very large stack of DVD-R).
>
> Regards,
> Spencer
>
> On Mar 24, 2010, at 12:52, John Nebel wrote:
> [...]
>   
>> Relevant to the LUG:  Given the high value of photographic images, and 
>> low cost of media and a PC internal tape drive, tape archiving is 
>> cost-effective.  There can be many backup copies and tapes may be kept in 
>> multiple locations.
>>
>> Disk redundancy is essential, but one must do both.
>>     
>
>
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