Proximal Data came out of stealth today with its AutoCache solid-state caching software designed to increase performance of heavily virtualized server environments using PCIe flash cards or solid-state drives (SSDs).
Solid-state caching software identifies frequently-accessed data and moves a copy to server-side PCIe flash cards or SSDs for better performance. The number of caching software applications has significantly grown over the past year to match the rise of server-side and array-based flash used in enterprise storage.
AutoCache will compete with EMC's VFCache, which uses similar software to manage data on its PCIe-based flash. Other independent software competitors include Nevex and Velobit. Earlier players in the market have been acquired by PCIe card vendors. Fusion-io bought ioTurbine, SanDisk bought FlashSoft and OCZ picked up Sanrad for its caching software. STEC also developed EnhanceIO software for its PCIe cards and solid-state drives (SSDs) and LSI has CacheCade for its PCIe flash cards.
Proximal Data claims AutoCache is unique because it plugs directly into VMware's ESXi hypervisors without requiring agents in guest operating systems. AutoCache inspects all of the data blocks going through ESXi and places hot I/O in the cache. Because it runs in ESXi, AutoCache supports VMware data movement features such as vMotion and Storage Distributed Resource Scheduler (DRS).
Proximal Data claims that because the software works in the hypervisor, AutoCache allows customers to deploy more virtual machines without affecting performance on hard drives.
Rich Pappas, Proximal Data's vice president of business development, said VM-specific caching will help flash take off in enterprise storage. He said server-side flash is more cost-effective than loading up a storage array with SSDs.
"You can't put everything on flash, so you have to figure out what to migrate from flash to disk," he said. "There are a lot of vendors putting flash on a box who claim they have addressed the I/O issue. But that box is expensive to buy and creates a rip-and-replace effect on operations. There are millions of virtual servers shipped per year, and I don't think you'll see millions of servers using flash on a box."
Like EMC's VFCache, Fusion-io's ioTurbine, Nevex CacheWorks and OCZ's XLV, AutoCache is a write-through cache. That means it caches reads for faster performance, but passes writes to the primary storage system. Others such as SanDisk's FlashSoft, STEC's EnhanceIO, and Velobit HyperCache also support cache write-back, which puts write data in cache first and moves it to primary storage later. Cache write-back is faster, but fresh data in cache does not match the data in primary storage.
Pappas said Proximal Data supports write-through cache because it offers better data protection.
"We do that so you don't have to do synchronous replication," he said. "With write-back cache, you have a lone copy of data in cache, and then you have to think about replicating it. We didn't want to re-invent the wheel for data protection."
Pappas said AutoCache is developed to run on all hypervisors, but will only support VMware ESXi 4.1 and 5.0 in the first version. It has also been tested with PCIe cards from LSI and Micron. Pappas said Proximal Data is working on certification from Intel and Fusion-io.
Compatibility and sales partnerships will be important for Proximal Data because many customers will pair the software with PCIe cards, and vendors with cards will push their own or their partners' software.
AutoCache pricing starts at $999 for cache sizes up to 500 GB. The software is expected to be generally available by the end of the month.
Storage analysts agree that Proximal Data's integration with VMware could make it stand out in what is becoming a crowded field of contenders.
"AutoCache sits on a hypervisor layer, and that's important because you don't need an agent for every virtual machine," said Arun Taneja, president of the Taneja Group. "There is no requirement to install anything else on the VM side. "
According to analyst Jim Bagley of Storage Strategies Now, "Proximal Data directly interacts with the storage I/O layer within the hypervisor, rather than having to install an agent on the guest OS [operating system]. From a management standpoint, that makes it easier if you want to clone a bunch of VMs or do vMotion. Otherwise, you have to touch every guest OS."