Advanced Technology for Maximum Performance
ESS Data Protection
Enterprise Storage Stack (ESS) is designed to protect your data. A number of techniques are used to create high reliability storage. Additional options are available to further enhance data protection and reliability.
Design Fundamentals: All data written by ESS is written in a FIFO linear stream to free space on the SSD set. This means that blocks are never updated in place. In place block updates are a common cause of data corruption in many designs. ESS gives you the benefits of a Copy On Write (COW) architechure without the overhead. ESS is also inherently designed to maintain the chronological ordering of updates. In many cases, chronological updates have very high overhead. Because of the linear nature of ESS writes, chronological updates are easy to maintain at full device bandwidth. This makes ESS storage inherently "crash clean" protecting file systems and other data structures.
Error Detection and Correction: one optional feature of ESS is the use of hashes to check data reliability on read, together with the use of micro-stripes to allow the repair of damaged data. This free feature is only available to OEM licensees and purchasers of WildFire systems.
Dual System High Availability: Dual system High Availability is intrinsically available to all customers. In the dual system environment, data received by one system is handed off to a second system, and acknowledgement of data receipt to the client does not occur until the duplicate system confirms data receipt. Accordingly, data from a client is stored on two systems rather than one. Proper configuration of a SAN then permits automatic fail over to the second system in the event the first system fails. The robustness of the system pair can be enhanced through the use of Raid-5 or Raid-6 media configuration with almost no performance loss. Similarly, dual-system HA is generally less expensive than Dual-Port HA solutions for any storage environment up to 10TB of capacity. Beyond this point, Dual System HA with its multiple disk sets has greater potential redundancy than can be achieved with Dual-Ported solutions.
Dual-Port, Dual Controller High Availability: Dual-Port solutions allow two controller cards in a single rack-mount chassis, or alternately two separate systems with external JBOD connectivity, to manage one set of SAS SSDs or a set of SATA SSDs with interposer cards. This technique is preferred by some customers and OEM licensees because it creates full redundancy, most commonly in a single chassis package. ESS special modules assure that the memory contents of one system, including new incoming data, are replicated on the second controller, and maintain almost instant switch-over when the primary system fails. This software is currently only available to OEM licensees.
Real-Time Logger Device: While our FIFO method satisfies the needs of most situations, some people want the assurance that all data received by a system is physically committed to hardware. To this end, ESS supports a a variety of nvRAM hardware solutions including PCIe memory card with built-in battery or SuperCap backup power. These cards only need to protect the small amount of data "in flight" during writes. This hardware/software solution is currently only available to OEM licensees and purchasers of WildFire servers.