Teradata Corp. is adding archiving to its burgeoning Hadoop arsenal with the purchase of RainStor Inc., a long-time partner that specializes in helping organizations squeeze as much information as possible into their storage space. It’s the fourth acquisition for the data warehousing giant in recent months and one of the most significant yet.

Born out of an internal project at the UK Ministry of Defence, RainStor hit the scene in 2008 with a technology designed from the ground up to cheaply store the petabytes of structured and semi-structured records that large companies in regulated industries stash away for compliance reasons. It uses homegrown compression algorithms to shrink data up to 40 times, Teradata products veep Chris Twogood told SiliconANGLE, which produces a multipler effect for the already compelling storage savings that Hadoop offers.

The platform also provides controls that make those economies attractive to organizations in highly regulated industries. RainStor prevents modifications after data has been written to disk – a requirement in some industries – and allows users to have files automatically deleted once the associated retention period expires.

But most importantly, RainStor keeps information accessible for auditing and other historical analysis at all times, which is its main advantage over traditional tape libraries. The data warehousing giant gave users its blessings to migrate their archives to the firm’s platform back in September last year with the release of an official connector, which takes some of the surprise out of the announcement. But it’s no less significant all the same.

The acquisition buys Teradata ticket into the new world of archiving, along with over 100 major RainStor customers across key sectors such as telecommunications and financial services.

Teradata intends to bundle RainStor’s software with its Hadoop appliance and hook it up to QueryGrid, a solution introduced in April that makes it possible to manipulate data across multiple systems at once. The deal also potentially provides another opportunity to sell implementation services from Think Big Analytics Inc., an earlier acquisition.

No financial details were disclosed for the deal, but the fact that RainStor raised a total of $26.3 million from investors indicates that the transaction is valued at least in the high eight digits, especially considering in light of the company’s blue-chip customer base. That would price this acquisition well above all three of Teradata’s other recent Hadoop-related buys, reflecting the importance of the transaction to its analytics strategy. After all, archiving is not merely another feature – it’s a prime use case for batch processing.