3.3.6.7Hardware Redundancy

Data protection strategies provided by the storage system hardware include cache memory, hot spare drives, background media scans, and channel protection.

Controller Cache Memory

Caution – Sometimes write caching is disabled when batteries are low or discharged. If a parameter called Write caching without batteries is enabled on a volume, write caching continues even when batteries in the command module or array module are discharged. If you do not have an uninterruptible power supply (UPS) for power loss protection, do not enable this parameter, because data in the cache will be lost during a power outage if the command module or array module does not have working batteries.

Write caching can increase I/O performance during data transfers. However, it also increases the risk of data loss if a controller (or its memory) fails while unwritten data resides in cache memory. Write cache mirroring protects data during a controller or cache memory failure. When write cache mirroring is enabled, cached data is mirrored across two redundant controllers with the same cache size. The data written to the cache memory of one controller is also written to the cache memory of the alternate controller. Therefore, if one controller fails, the alternate can complete all outstanding write operations.

To prevent data loss or corruption, the controller periodically writes cache data to disk (flushes the cache) when the amount of unwritten data in cache reaches a certain level, called a start percentage, or when data has been in cache for a predetermined amount of time. The controller writes data to disk until the amount of data in cache drops to a stop percentage level. Start and stop percentages can be configured by the user. For example, you can specify that the controller start flushing the cache when it reaches 80% full and stop flushing the cache when it reaches 16% full.

Low start and stop percentages provide for maximum data protection. However, in both cases, this increases the chance that data requested by a read command will not be in the cache, decreasing the cache hit percentage for writes and the I/O request. Choosing low start and stop percentages also increases the number of disk writes necessary to maintain the cache level, increasing system overhead and further decreasing performance.

Data in the controller cache memory is also protected in case of power outages. Command modules and array modules contain batteries that protect the data in cache beekeeping a level of power until the data can be written to the drive media. If a power outage occurs and there is no battery or the battery is damaged, data in the cache that has not been written to the drive media will be lost, even if it is mirrored

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Sun Microsystems 5310 NAS manual Hardware Redundancy, Controller Cache Memory
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5310 NAS specifications

Sun Microsystems, known for its innovative computing solutions, launched the Sun 5310 Network Attached Storage (NAS) system, which marked a significant advancement in the realm of storage solutions in the early 2000s. The 5310 NAS was designed to provide high-performance, reliable, and scalable storage tailored for enterprise environments.

One of the standout features of the Sun 5310 NAS is its file-serving capabilities, which support multiple protocols, notably NFS (Network File System) and CIFS (Common Internet File System). This dual-protocol support allowed organizations to seamlessly integrate the NAS into diverse IT ecosystems, facilitating interoperability between UNIX, Linux, and Windows systems. The enhanced file-sharing capabilities made it an ideal solution for businesses with mixed operating environments.

The Sun 5310 NAS incorporates cutting-edge technologies to ensure high availability and data integrity. The system utilized a RAID (Redundant Array of Independent Disks) technology, providing various RAID levels to protect against data loss while optimizing performance. Additionally, the device featured hot-swappable drives, enabling maintenance and upgrades with minimal downtime, a crucial factor for business continuity.

Equipped with advanced management software, the Sun 5310 NAS offered users an intuitive interface for monitoring storage health and performance. This software included comprehensive reporting functionalities that allowed IT administrators to oversee usage patterns and capacity planning efficiently.

Scalability was another defining characteristic of the Sun 5310 NAS. The system could easily expand with additional storage modules, accommodating the growing needs of an organization without the necessity for complete system overhauls. This flexibility ensured that businesses could adapt their storage solutions to meet evolving data storage needs without incurring significant costs or disruptions.

In terms of performance, the Sun 5310 NAS featured high I/O throughput achieved through its robust hardware architecture and optimized file serving capabilities. This performance baseline was crucial for organizations that relied on heavy data workloads and required rapid access to information.

In summary, the Sun 5310 NAS from Sun Microsystems embodied a forward-thinking approach to network storage, blending reliability, scalability, and multi-protocol support. Its user-friendly management software, combined with the robustness of RAID technology and hot-swappable drives, made it a preferred choice for enterprises looking to streamline their storage infrastructure while safeguarding critical data.
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