3.9 Chapter Summary

The Software Spectrum

• Purchasing processes are shifting from hardware-centric decision making to identifying best platforms for software and applications.

• The underlying hardware must be matched with effective software management systems.

• Storage software helps administrators effectively get control of their storage domains.

3.1 Framework for Storage Management Software

• Storage management breaks down to infrastructure management, transaction management, and recovery management.

• Infrastructure management has a platform focus and includes SAN management and resource management.

• Transaction management has an application focus and includes data coordination and policy management.

• Recovery management has an availability focus and includes data protection and high availability.

3.2 Storage Network Management

• SAN management provides network-centric administration features.

• Discovery identifies all devices within a storage fabric.

• Zoning and configuration determines which storage devices can access and modify each other.

• Zoning can take place through port-based (hard) or WWN (soft) mechanisms.

• SAN topologies serve as a useful tool for mapping physical layouts of storage.

• Monitoring keeps administrators aware of the general health of the SAN.

• Protocol conversion takes place in the SAN between Fibre Channel and IP transports.

• Different device types (iSCSI and Fibre Channel) and device attachment methods (direct or via a SAN) require different protocol conversion mechanisms.

• Documented storage policies and procedures, including cabling and labeling of devices, helps speed recovery in the event of disaster.

3.3 Storage Resource Management

• Storage resource management helps centralize control of storage devices.

• SRM applies to HBAs, SAN switches and routers, and storage subsystems.

• Subsystem efficiency can be tracked through SRM and can aid in capacity planning.

3.4 Data Coordination

• Data coordination takes place through file systems and volume management.

• File systems deliver abstraction between logical volumes and files.

• Volume management delivers abstraction between disks/LUNs and logical volumes.

• File systems and volume management aggregate storage resources to common presentation layers .

3.5 Storage Policy Management

• Storage policies use information from resource management to enhance efficient use of storage.

• Policies include security and authentication; capacity, content, and quota management; and quality of service for storage and storage networks.

• Storage policies are implemented and maintained through an ongoing process.

• Capacity management optimizes the use of existing storage resources.

• Security and authentication policies guarantee privacy and data integrity.

• Quality of service features enable delivery of guaranteed resources.

3.6 Data Protection

• Data protection schemes present various cost-availability tradeoffs.

• Tape backup delivers low “cost-per-megabyte storage with low speeds and long restore times.

• Tape cartridges provide flexibility for onsite and offsite storage.

• With SANs, tape libraries can be shared across the infrastructure, including backup for NAS.

• Disk backup has a high cost per megabyte with high speeds and short restore times.

• Point-in-time and snapshot backup tools enable sequential rollback to restore databases to predisaster or precorruption states.

• Hierarchical storage management helps minimize total storage costs by moving infrequently accessed data to lower cost media.

3.7 High Availability

• For guaranteed uptime, disk backup solutions require mirroring or replication, or both.

• Mirroring provides the highest availability via instant restore times.

• Synchronous and asynchronous replication trade restore time for distance and enable remote backup solutions for site-specific disasters.

3.8 Virtualization

• Virtualization is often misunderstood due to bundling of other storage software features in the term .

• Basic virtualization is the homogeneous presentation of heterogeneous storage.

• Data-protection features like backup or availability features like mirroring and replication can reside on top of a virtualization layer.

• Virtualization can be deployed across host, fabric, and subsystem layers.

• Options exist for customers to balance storage control points through different virtualization deployments.