The first caching solution to provide write-back capability was PernixData FVP. Finally, there is a specific framework VAIO to simplify the introduction of new features in the I/O storage path. Actually, there is a list of solutions designed and certified for VAIO, available in the document at http://partnerweb.vmware.com/comp_guide2/pdf/vi_vaio_guide.pdf.

• SanDisk FlashSoft 4.0: This was the first host-based caching software to achieve VMware Ready™ certification for guaranteed compatibility, reliability, and support. It also introduces support for VMware-supported datastores, virtual disk acceleration, improved performance and stability, and integrated management through the vSphere web client GUI. But with the acquisition of SanDisk by Western Digital, the future of FlashSoft is not so clear.
• Infinio Accelerator 3.0: A software-based server-side cache that provides high performance to any storage system in a VMware environment. It increases IOPS and decreases latency by caching a copy of the hottest data on server side resources such as RAM and flash devices. Native inline deduplication ensures that all local storage resources are used as efficiently as possible, reducing the cost of performance. Results can be seen instantly following the non-disruptive, 15 minute installation that doesn't require any downtime, data migration, or reboot. Infinio supports both VMware vSphere ESXi 6.0 and 6.5 (Standard, Enterprise, or Enterprise Plus) and works with any VMware supported datastore, including a variety of SAN, NAS, and DAS hardware supporting VMFS, VVols, and vSAN.
• PrimaryIO: This is an emerging provider of performance optimization solutions for business-critical applications, that on March 2016 announced the first version of the Application Performance Acceleration (APA) solution. PrimaryIO APA was probably the first product born directly on the VAIO framework and seems very promising. It has also a cluster-wide caching where one host can use the SSD cache from another host in a better way.

There are also other solutions, not based on VAIO filtering, that use kernel modules, such as with Pernix FVP. Anyway, this approach is less flexible compared to VAIO filtering, because a kernel update can break the custom kernel modules.