AllThingsD published on Friday that the deal will be announced this coming Monday--although a buying price is not expected to be revealed.
It's worth noting that neither company have publicly confirmed the merger yet.
Until then, AllThingsD estimated (based on other rumors) that Violin paid anywhere between $200 million to $300 million for GridIron, located in Sunnyvale, California
For reference, the Mountain View, California-based Violin Memory specializes in producing flash memory arrays for enterprise data centers.
With this acquisition, it is likely that Violin will be integrating GridIron's data center acceleration appliances with its solutions around virtualization, as well as mission-critical apps.