CacheIQ was at least in part a reboot of an earlier NAS acceleration startup StorSpeed, with Greg Dahl holding executive positions in both incarnations. The basic premise of both companies' technology was to make the NFS cache strictly a networking function without actually terminating NFS sessions at the caching appliance, as Avere and Alacritech do. Instead, the product either responds to requests with data from the cache or passes the requests on to the back-end NAS filer.
StorSpeed took the ambitious approach of developing custom hardware with dedicated ASICs, which complicated its path to market. CacheIQ adapted the technology to run on standard servers and Ethernet switches, and attracted $6 million dollars in funding during its two year life.
Of the remaining caching appliance vendors, Avere seems to be the healthiest, in part because the company has extended its technology from simply being an external cache to accelerate your old, creaky, NAS box for local users. Avere's FXT appliances can also provide a distributed cache, allowing users at multiple locations to share data in a central NAS appliance without suffering the huge performance hit a WAN link's low bandwidth and high latency would ordinarily cause. In addition, a single logical namespace across multiple back-end filers simplifies management.
The early leader in the market, Gear6 (since absorbed into Violin Memory for a handful of magic beans), learned the hard way that if all you have to sell is an external accelerator, you can be in a world of hurt if the back-end storage vendors add their own superchargers and nitrous injection systems. DataRAM and Gridiron make Fibre Channel caching appliances for the SAN market, which can provide a performance boost for folks that can't just add SSDs to their existing arrays, but may be threatened by server-side caching products that can solve the same problems at a lower cost.
Because NetApp has been closed-mouthed about the whole deal, I don't know anything about how much it paid, though my sources say that CacheIQ's team and investors aren't unhappy. Unfortunately, NetApp isn't going to be selling CacheIQ's RapidCache appliances to EMC Celerra and VNX customers: The company said in its earnings call that we should think about Cache IQ as more of a technology tuck-in and that the company has discontinued the product.
Both CacheIQ's RapidCache and NetApp's FlashCache (the product formerly known as PAM) are read caches that don't accelerate write access, so there's a philosophical fit, but with RapidCache dead as a product line, I'm having difficulty understanding where the technology actually fits. NetApp doesn't have the history of integrating acquisitions that EMC or even Dell has, so it will take some time before I can say whether this turned out to be a good deal.