CAS manages using the SSD storage as a cache layer for slower storage data (e.g. spinning hard drives). A cached copy of recently used data from slower storage is kept in faster SSD storage to improve I/O performance.[1] CAS entered Intel's product line as the result of Intel's August 2012 acquisition of a Canadian start-up company Nevex Virtual Technologies;[2] Intel re-branded Nevex CacheWorks product to CAS with the release of version 2.0 in December 2012.[3] Versions of Intel CAS are available for Windows Enterprise, Windows Workstation, and Linux.[2][4]
CAS for Windows is an application-aware file-based cache, which can be tuned by system administrators. Additionally, it integrates with the operating system's buffer cache, creating a multi-tier cache architecture.[5][6] CAS is also aware of some virtualization technologies like vMotion, maintaining a hot SSD cache during a VM migration.[7]
CAS works with the enterprise-class Intel SSD products, such as the DC S3700 SATA drives and the DC P3700 NVMe PCI Express devices.[2] It also works with cache devices across SANs.[8] Intel CAS for Linux consists of a GPL'd source loadable kernel module paired with a closed source user-space admin configuration tool. The CAS for Linux version supports CentOS, Red Hat Enterprise Linux and SUSE Linux Enterprise Server.[7] The Windows Enterprise version currently runs only on the 64-bit flavors of Windows Server 2008 R2 SP1 and Windows Server 2012 R2; 32-bit versions are not currently supported.[9] The Windows Workstation version currently runs on only the 64-bit flavors of Windows 7, Windows 8.1, and Windows 10; 32-bit versions are not currently supported.
The current version of CAS for Linux supports write-through, write-back, and write-around caching. The Windows versions of CAS support write-through and write-back caching.[8]
A workstation version, called CAS-W, was announced in September 2013 by Dell; Dell's announcement states an exclusive agreement with Intel to offer CAS-W only for Dell Precision workstations.[10][11]