I suspect you are using the wrong term. Absolutely everything a company or a third party has is potentially "discoverable" unless it is privileged. The question is fundamentally who pays the cost of searching. If it is records you use, the defendant pays the cost. If you don't use the records the plaintiff pays the cost.
pretty good piece at
http://www.craigball.com/What_Judges_Should_Know_About_Discovery_from_Backup_Tapes-corrected.pdf
Good article and I may have used the wrong term, but as of last year no judge had ordered that any back-up tapes ever be mined for data.
From the article, since the company has never used backup tapes for any reason other than a true catastrophe then this is the argument that has always held up in court. (see the first 2 points that a judge considers).
I know that for certain (all?) criminal investigations this argument would not be valid. eg if an employee was suspected of being a paediophile and being investigated by the FBI then all his e-mail and browsing history must be produced.
The court may want to inquire:
• Does the responding party routinely restore backup tapes to, e.g., insure the system is
functioning properly or as a service to those who have mistakenly deleted files?
• Have any of the backup tapes at issue been restored in other circumstances and thus
accessible as information in other cases or held by third parties?
• Does the responding party have the system capacity and in house expertise to restore the data?
Not everyone has the idle system resources or personnel required to temporarily restore a prior
version of the data alongside the current version.
• Can responsive data be searched and extracted without wholesale restoration of the tapes?
Emerging software and tape technologies sometimes make this feasible.
• Have you compared your projected in-house restoration cost against the services of so-calledyourself” is not always cheaper.
“tape houses” equipped to process large numbers of tapes at competitive prices? “Do it