Yes, FlashSoft is different than vFRC in ESX 5.5 in many ways as described below:
1. SanDisk understands SSD medium very well and knows what works best to get the most optimal read/write performance out of the SSD device.
It uses following techniques to get the best out of the SSD.
2. FlashSoft uses the SSD device as a ‘circular buffer’ writing to it mostly sequentially. This helps get a consistent read/write performance at the same time increasing the SSD life (sequential writes causes less wear which frees up SSD control cycles to better serve reads/writes instead of getting those cycles consumed for wear leveling).
3. FlashSoft uses flow-control mechanisms (called read/write gates) that control the flow of reads and writes to the SSD. It ensure that the reads and writes issued to the SSD device are not randomly mixed with each other. This helps achieve a consistent read/write performance from the SSD over a longer period of time.
4. FlashSoft writes to the SSD device in variable block sizes, which means that it can accelerate applications doing reads/write with variety of block sizes, without having to choose a block size at configuration time.
5. FlashSoft dynamically allocates cache capacity to various VMDK file that it accelerates on a given host. Hence as VMs go in and out of ESX hosts due to DRS/vMotion, the SSD capacity is optimally managed for the active VMDKs being accelerated on a given host at any point in time. This ensures that cache capacity is not wasted due to static allocation. This dynamic cache capacity management also means that when VMs vMotion from one host to another, the other host does not necessarily have to have fixed available cache capacity for the VM to power-on.
6. FlashSoft cache contents are persistent across VM and host reboots because it stores the metadata needed to operate the cache on the SSD device along with the data. Hence cache performance is not degraded across VM and host reboots.
7. FlashSoft requires extremely low host resources to run the caching engine. e.g. default max memory utilization is 140 MB to accelerate up to 256 VMDK files per host.
8. FlashSoft allow and individual VM use the whole cache beyond 400G.
9. FlashSoft provides an single view of the VM's that are accelerated or unaccelerated for quick visual validation
Though it runs as a module within the hypervisor, FlashSoft is fundamentally a storage technology. It gathers exact statistics on the I/O profile of the vmdk files accessed by the VMs running on the host. Caching parameters can be tuned to optimize performance, which can be very important for workloads that differ from a "normal" use case.
FlashSoft is available for all versions of ESXi 5.x (Essentials, Essentials Plus, Standard, Enterprise, & Enterprise Plus)
If you want to evaluate FlashSoft from SanDisk Please visit http://www.sandisk.com/flashsoft-connect
James Rosikiewicz
Senior Solutions Architect | Eastern North American Software
SANDISK
