DRAM! Speedy software upstart PernixData's caching up fast

Caching speed upped by several orders of magnitude

VMware IO cacher PernixData has upped the quick access ante by caching virtual machine disk IO in DRAM — much faster for data access than flash.

The startup’s FVP software runs in the ESXi hypervisor, and it's also added user-defined fault domains and adaptive network compression to its clustering technology.

FVP accelerates any storage IO: file, block or object, and requires no VM or app alteration. By adding DRAM caching, it speeds up guest VM data access by several orders of magnitude.

Data access by memory lookup is in the nanosecond time scale, while flash access is in the 15-100 microseconds ballpark – for the disc, think 1,000 times slower, at 4-7 milliseconds.

An Infinio blog uses an analogy to make the relative differences clearer.

Let’s say a single memory data access takes a minute. If this is the case, then a flash lookup would take one or two months, while accessing the data from disk would take up much of a decade.

Guest VM IO can be speeded up so much by effective caching that their overall speed goes up by factors of 10.

Look at it another way. A FVP cached server can support more VMs with flash caching and more again with DRAM caching. You need fewer servers to run your VM population.

FVP can be subscribed to, or you can buy a perpetual licence. Product options have multiplied with V2:

• FVP Standard — read and write acceleration and cluster tech
• FVP Enterprise — as standard plus topology-aware write back acceleration, adaptive resource management, and DR integration
• FVP for VDI — priced on a per-desktop basis
• FVP Essentials Plus — as standard, and for up to three hosts and 100 accelerated VMs.

FVP Enterprise supports servers with caching on all flash, all RAM or a hybrid of the two. The other product editions support all-flash or all-RAM. FVP Enterprise can be obtained through subscription or a perpetual license. FVP Standard is a license purchase only. FVP Essentials Plus replaces a previous FVP SMB edition.

As long as guest VMs make off-server data requests to shared storage then FVP’s caching should be able to speed such accesses. However, the more server-side SANs come to the fore and the more all-flash server-side SANs are deployed, the less relative advantage PernixData offers. However, the advantage is that DRAM caching over flash storage access is still enormous, and only in-memory application working set data would render FVP pointless.

PernixData claims it now has 200 customers in 20 countries, and 250 resellers in 50 countries, meaning resellers in many countries have yet to strike their first deal. Existing customers have optimised around 120,000 VMs.

This is, frankly, peanuts, a derisory total compared with what’s out there, and what’s possible. There are tens of millions of VMs around the world ready to be accelerated by caching.

PernixData claims it earned 50 per cent more revenue in its first year than any other software infrastructure company ever. Its total addressable market must be huge and it beats me why VMware hasn’t bought the company. Maybe VMware has its own caching software in development? ®