What is the benefit of tape storage?

[natekruser]

This may seem like an incredibly naive question, but what is the benefit of tape backup?

 

I currently run a Retrospect Server connected to 2.0 TB of onsite disk storage and 2.0 TB of offsite disk storage. Each of the storage units is in a RAID 5 configuration for redundancy.

 

The backups cover roughly 50 Windows and Mac OS office computers, and 2 servers. With Proactive backups and default grooming I have backups up to three months old.

 

I understand that tapes allow someone to build up a 'library' of backups, so you might be able to retrieve files from a year or more previously. This system has been operating for close to a year. In that time I have not needed to recover anything over a week old. Are older backups really worth the cost of the tapes they're on?

 

I understand that tapes can be taken 'offsite' in case of a fire or other location specific disaster. But offsite drive storage solves the same issue, with higher availability. I don't see any advantage in tapes for movement offsite.

 

It seems as though tapes are a ubiquitous component of other backup systems. I fear that I am overlooking some key detail that makes the neccessary. I am very careful and serious about my backups. I have built up our current system from scratch, learning as I went. I argued for our purchase of Retrospect, a server to run it on, and the two storage units.

 

I want to maintain the most useful, robust, and available system I can but I lack the experience gained by survivng disasters. I'd rather learn from someone else's than my own if I can!

 

Please tell me, if you can: Who needs tapes once you have a Retrospect server and some big RAIDs.

Thank you!

[rhwalker]

Quote:

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I understand that tapes allow someone to build up a 'library' of backups, so you might be able to retrieve files from a year or more previously. This system has been operating for close to a year. In that time I have not needed to recover anything over a week old. Are older backups really worth the cost of the tapes they're on?

...

Who needs tapes once you have a Retrospect server and some big RAIDs.

 

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We do. It all depends on the nature of your data and your specific backup requirements.

 

In our business (patent and trademark law), the trademark files can last forever and the patent cases have a life of about 20 years. We need those files online all the time. It might be years between access of a certain case, and we might not discover until years later that some file inadvertently became deleted years before. We can go back to any snapshot on any day from 1992 (as long as Retrospect stays in business).

 

There may be other requirements for a publicly traded company (e.g., records retention, availability, etc.).

 

Somewhat unrelated to the above, our floor of our office building had a fire almost two years ago. We lost all of our computers. Our fireproof filing cabinets preserved all of our papers. Our offsite Retrospect tape backups (we have alternating backup sets daily, one set goes offsite permanently, one set stays onsite permanently; we never reuse tapes) saved us, and no data was lost. But those are our needs, not yours.

 

There is a pretty good discussion of the issues involved in backup here: What Should a Good Backup Policy Address?

 

Hope this helps,

 

Russ