constituted with the same structure as that on the master system. File system segments, or extents, are created on the mirror system in numbers and sizes matching those on the master system. In the case of a master reboot, this state consists of simply validating each extent on the mirror system.

The mirror volume is identical to that of the master, except that the partition type is reported as NBD, and all access to the volume outside the mirror service is limited to read-only. The mirror volume will remain unmounted until the entire creation and replication processes have completed.

As in the INIT state, minor errors encountered during the MAKEPARTS state cause the mirror to enter the RESET state, and severe errors drive the mirror into the ERROR state. Some of the more severe errors that might be encountered are a volume on the mirror system with the same name as that on the master system, insufficient disk space on the mirror system, or failure to transfer file system extent information to the mirror system.

When the mirror has been successfully created and/or validated, the mirror enters the READY state. At this point, the master system determines whether to proceed to a replication state or the INSYNC state.

4.2.2Mirror Replication

Mirror replication is a process that is executed in both the REPLICATE and OUTOFSYNC states; the two states are operationally identical. The REPLICATE state is entered only when the mirror is first starting; either when it has just been created, or when the master system is rebooted while replicating. The OUTOFSYNC state is entered if the mirror cracks while in the sequencing phase. The process of sequencing is explained further below.

During replication, all allocated disk blocks on the volume are copied directly from the master to the mirror system. This process bypasses the file system transaction mechanism normally used in volume read and write operations. Blocks are read from disk and transferred to the mirror system, where they are written straight to their home locations on disk. The mirror buffer is not used by the replication process.

However, the mirror buffer is used by the master file system, during replication, to store file system transactions that need to be transferred to the mirror system. The master volume is live during replication; any changes to the volume must be stored in the buffer until replication completes, at which time those changes are transferred to the mirror system. It is very important that the mirror buffer is large enough to store all transactions while the master is initially syncing itself with the mirror system.

Chapter 4 StorEdge File Replicator 4-11

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Sun Microsystems 5310 NAS manual Mirror Replication
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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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