Reliability
The subsystem supports a complete list of RAID configuration levels in the forms of logical drives, logical volumes and logical partitions. Multiple RAID configurations can co-exist within one enclosure, each with distinct write policy, stripe size, and optimization modes. Hot rebuild and numerous fault correction mechanisms ensure the highest standard of RAID protection.
Safe distribution of data is embodied in many ingenious fault-preventive designs. From memory ECC, write-verify, parity regeneration, parity update tracking, Media Scan, to battery backup protection, your data is warded against factors that might cause data inconsistencies. For example, the subsystem is capable of managing storage arrays with fault containment algorithms. If a critical component fails, e.g., a battery module, the subsystem automatically disables its write-back caching and assumes the conservative writethrough mode. Algorithms like this guarantees that data is reliably managed and all risk factors are always carefully checked.
Availability
The A12U and A08U subsystems are equipped with field-hardened technologies that ensure data protection and a simple, centralised management.
The subsystems are managed by firmware developed with sophisticated RAID technologies and redundant component designs. Incorporating various data protection algorithms and featuring RAID levels 0, 1(0+1), 3, 5, 10, 30, and 50, the subsystem actually offers capabilities only seen in enterprise-class solutions.
To ensure a high level of system availability, critical components such as disk drives, power supplies, and cooling fans, are all redundant and hotswappable. Modules are integrated with the main signal path PCB via board-to-board or interface specific connectors to eliminate points of failure.
Assisted by GUI management software, the operating status of all components can be constantly monitored through a local or remote console.
Sericeability
All critical modules are housed in their own removable canister, including hard disk drives, power supplies, battery modules, and cooling fans. In the event of component failure, each can be replaced within seconds. Spring screws, securing latches, and key-locks all help provide easier access to the modules.
A variety of configuration and monitoring methods are available, either locally via the LCD keypad panel and the text-mode RS-232C terminal utility, or remotely through the Java-based GUI manager. All fault conditions, including module failure and abnormal voltage and temperature readings, are instantly reported. A system administrator can choose to be notified via LAN broadcast, SNMP traps, email, fax, SMS, ICQ, and MSN messenger when he is away from the installation site. Even the notification utility can be installed redundantly on two different machines to avoid the chance of blind time due to a simple component failure.
Intelligent Drive Handling
- Media Scan: repairs data stored on bad drive sectors from adjacent stripes
- Task Scheduler: hands free, pre scheduled Media Scan operation on disk drives
- Replaces or clones drives showing SMART detected defects
- Manually clones of disk drives showing defects
- Verifies data after normal writes, rebuild writes, or Logical Drive initialisation
Adaptive Write Policy (Write-back/Write-through)
- Optimises writes performance on receiving sequential write requests using the Write-through mode and temporarily disables synchronised cache communications
- Automatically switches policry to adapt to random or sequential I/O requests
Guaranteed Latency I/O
- Designed for "no drop-frame" applications such as video streaming
- Fast return of read requests by generating data from adjacent stripes when a drive fails or bad sectors cause delays
