Adtron SmartStorage™
Adtron designs and builds standards-based data storage framework, delivering world-class data solutions to the industrial marketplace. Adtron SmartStorage™ framework delivers data storage solutions with outstanding durability, reliability and high availability across a range of storage media, such as solid state flash disks, rotating hard disks and removable media, and host interfaces including SATA, IDE, SCSI and Ethernet.
Durability
Durability refers to a device's ability to resist the effects of a specific operating environment. Each type of storage media has its own unique operating characteristics within an environment. Industrial applications may vary greatly in their environments and, as a result, no single storage media can be characterized as ideal in every case for a specific embedded application. Harsh environments can significantly affect the operating lifetime or mean time between failures (MTBF) of a device. Therefore, environmental conditions must always be considered when determining the durability specification for a storage device to help ensure the required degree of system reliability. For example, Adtron flash disks are designed for non-fail operations in defense and aerospace applications, where the economic and human cost of lost data is high.
Environmental attributes that affect durability of storage devices include:
- Temperature range for both operation and storage
- Temperature gradient (rate of change)
- Humidity and condensation
- Altitude and atmospheric pressure
- Power consumption and heat contribution
- Shock and vibration
Reliability
Reliability refers to the operating life of a device within a defined functional usage—such as power-on time and activity duty cycle — as well as its operating environment. Reliability is often referenced as a statistical number called MTBF (mean time between failure). A number of methods exist to predict and measure MTBF. At Adtron, MTBF is predicted using MIL-HDBK-217 and Telcordia prediction methods with validation performed through parametric and accelerated life testing. MTBF varies based on the environment and the storage device durability. Where the cost of lost data is high—such as in semiconductor wafer fabrication—a flash disk may be the storage device of choice. In other industrial applications—such as telecom access control and accounting node—mirrored hard disks or a single hard disk may be adequate. Economic value frequently determines the level of reliability required by an application.
Considerations for determining application reliability requirements may include:
- Operating environment and device durability
- Cost of failure and value of data
- Operating field life requirement
- Power-on and duty cycle of operation
Adtron Flashpak® Flash Disk Reliability
| Prediction Method | MTBF* |
|---|---|
| MIL-HDBK-217F | 250,000 hours |
| Telcordia | 1,400,000 hours (ground fixed, uncontrolled) |
| Telcordia | 2,900,000 hours (ground fixed, controlled) |
High Availability
Availability is a measurement of the percentage of time a system operates properly during a given period. For most industrial applications, the target availability is 100% during mission critical times. In reality, however, with complex systems, the probability of a failure reduces this metric down to less than 100%. For many systems, in anticipation of a component failure, redundancy is built in to help overcome the failure of any single component. Should a component fail, availability is impacted by the fail-over time and the MTTR (mean time to repair). Careful redundancy management yields high availability in some systems up to five nine's (99.999%) availability.
A mirrored RAID disk system statistically has lower MTBF reliability since it employs two disks instead of one. However, the redundancy also provides enhanced failure management and higher availability. The probability of a simultaneous failure of two parallel devices is virtually zero. Therefore, if a failed disk can be replaced before a second disk fails, the system may run non-stop. Adtron ActiveRAID™ disk subsystems are designed to allow hard disk failure and replacement without impacting system access to the redundant disk.
Considerations for determining application availability requirements include:
- Inherent reliability of the system components
- Build-in redundancy of low reliability elements
- Environmental affects on reliability and redundancy effectiveness
- Ability to repair and associated MTTR (mean time to repair)
System compatibility
At the highest operational level, system compatibility covers the requirements of:
- Capacity (most relevant in software and system management)
- Performance (related to bus performance; often misunderstood)
- Form factor (2.5-inch, 3.5-inch , cPCIM®, ATCA, VME etc, as determined by application requirements)
Storage interface
Interface is the physical layer, such as connector and electrical levels, as defined by standards such as SCSI, RS422 and ATA. These are already chosen by the designer based on the computing platform.
Storage protocol
Storage specification level such as ATA-5, SCSI-3, iSCSI, NFS, etc.
Storage emulation
‘Glues’ storage protocol and media management sections together and establishes data handling processes including random access, fixed or removable disk as well as sequential access including tape operations.
Media management
Based on the required durability, reliability and availability, the choices for Media Management include Adtron ArrayPro™, Adtron ActiveRAID™ technology using either RAID 0, RAID 1, RAID 5 or JBOD.
Media Control
In conjunction with the required media management layer, Media Control refers to where the media protocol and physical connection is made.
Environmental Suitability
It is desirable that the system storage element should perform to the system reliability requirements within the specified environment. Adtron offers the range of single disk, RAIDed disk and flash disk to encompass the durability demands of temperature, shock, vibration, EMC and altitude. As important as the system operational compatibility, the environmental suitability must be carefully established to manage cost and value tradeoffs.