OCZ has just introduced a new software/hardware combination aimed at accelerating the performance of Microsoft SQL Server. The OCZ ZD-XL SQL Accelerator combines a custom PCIe SSD with caching software optimized for the SQL Server workload. The company boasted that this product won the “Best of Interop 2013” award, a distinction certainly worth crowing about!
How does this product differ from standard caching software? OCZ tells us that the key elements required to efficiently accelerate SQL Server applications are:
- Flash volumes
- Flash caching
- Cache policy optimization
- Cache pre-warming
all of which have been designed into the ZD-XL SQL Accelerator architecture. The first two of these are pretty obvious. Policy optimization is limited in general-purpose caching software, but can be highly-tuned in caching software dedicated to a single task, although there’s always the worry that an upcoming major revision of the application may render this tuning suboptimal at some later date. Pre-warming is also somewhat dependent on the application’s stability, but is also linked to workflow, which is very likely to follow a rather predictable pattern (like closing out the books every evening or preparing financials for quarterly reviews.)
The PCI Express (PCIe) flash-based ZD-XL SQL Accelerator hardware, a slightly-modified version of OCZ’s RevoDrive PCIe SSD, resides on each server’s PCIe bus. Another feature called SQL Server AlwaysOn can be coupled with the flash to support high-speed replication for high availability installations. Caches in multiple servers can be pooled into a single large volume. OCZ offers this product in three capacities, 600, 800, and 1,200GB ranging in price from $7,800 to $15,200.
In its briefing the company pointed to a couple of very successful installations; in one of these the ZD-XL SQL Accelerator outperformed a competing configuration based on five PCIe SSDs.
The SSD Guy quite naturally compared this to other products that have been introduced for similar applications. Since the ZD-XL SQL Accelerator is tailored to a single application it brings to mind the MySQL acceleration boxes introduced in 2008 by both Virident and Schooner (now a part of SanDisk.) These two systems combined an off-the-shelf server with either on-board flash or standard SSDs teamed with optimized versions of the open-source MySQL program to render blisteringly-fast database queries. Neither achieved market success owing to the trend away from customized hardware toward virtualization.
Another product that is somewhat similar is SanDisk’s FlashSoft caching software, which is not tuned to any specific program. It is very likely that the SQL tuning in the OCZ product allows it to out-perform the general-purpose FlashSoft product. What is more interesting to me, though, is the fact that SanDisk’s product supports any SSD that is attached to the system, whether it is SanDisk’s or a competitor’s, while the OCZ ZD-XL only works with a customized OCZ SSD. The two companies have very different approaches to marketing their flash products. I will be watching carefully to see which brings greater success.
