| Storage System Control Points -
Storage networks allow the movement of storage intelligence across the entire infrastructure. -
Storage intelligence or services act as solution control points. -
Historical architectures help present a picture of the future. -
There are pros and cons for storage services residing within host, fabric, and subsystem layers . -
Networking plays a crucial role and should not be relegated to plumbing. 4.1 Storage Service Deliverables -
Storage services fit into the overall framework for storage software, including infrastructure, transactions, and disaster recovery. -
Services include -
Manageability (e.g., simplified administration) -
Capacity (e.g., virtualization) -
Recoverability (e.g., point-in-time copies) -
Performance (e.g., increases I/O performance beyond single-disk performance) -
Security (e.g., access control) -
Availability (e.g., beyond disk failure with mirroring) -
Categorization helps clarify locations. 4.2 Brief History and Evolution of Storage -
A broad historical perspective across compute and storage platforms reveals a trend toward distributed systems. -
The mainframe era represented high-cost, single-vendor, centralized storage. -
The minicomputer and clustering era delivered multinode storage access for decentralized storage. -
The client-server era led to split storage architectures between data centers, departmental servers, and desktops. -
Distributed Web, application, and database servers require distributed storage in virtualized storage pools. -
All storage services must scale in terms of -
Size (e.g., number of nodes) -
Speed (e.g., throughput or I/Os per second) -
Distance (e.g., geographic reach) -
First-generation single-table routers were replaced with more scalable, higher performing distributed systems. -
A router is essentially a network within a chassis. -
Similar design principles of distributed services apply to storage. -
Intelligent nodes with distributed storage services facilitate scalable, high-performing systems. -
An intelligent storage network leaves options for storage services locations. 4.3 Placing Storage Intelligence -
Storage services locations depend upon application requirements, cost points, network utilization, and preferences. -
No hard and fast guidelines apply; however, certain storage services make sense in some areas over others. -
RAID 0/5 as compute- intensive operations tend to do well when located within the subsystem. -
RAID 1 (mirroring) is similar to network multicasting. -
Multicasting algorithms suggest replication as close as possible to the receiving nodes to minimize network utilization. -
With RAID 1, network-based mirroring is the optimized deployment for the best network utilization. -
Additional network ports can offset server HBA or subsystem controller ports. -
Network ports are often less expensive than end system HBA or controller ports. -
Attribute-based storage is best delivered by network-based storage services. -
Network location for storage services allows for -
Visibility -
Access and Topology -
Reactive Capability 4.4 Building Blocks of Distributed Systems -
Distributed systems have proven to be the most scalable solutions. -
Core computing functions include memory, CPU, I/O, and networking. -
Traditionally, memory and CPU functions outstripped I/O and networking. -
I/O and networking advances put building blocks on even ground. -
Interconnect advances (Fibre Channel and Gigabit Ethernet) allow I/O and networking to keep up with memory and CPU performance gains. -
I/O and networking similarities converge, leading to architectural overlap and consolidation. 4.5 Network Control Points -
Storage network or fabric is the disintermediary between traditional host and target storage services implementations . -
Interconnects have traditionally been separated by bandwidth, node scalability, and throughput. -
Gigabit Ethernet, 10 Gigabit Ethernet, and iSCSI allow Ethernet and IP to encroach on the storage-dominated interconnect landscape. -
Ethernet also is moving into the MAN and WAN. -
Cost and management advantages will force network consolidation. 4.6 Balancing Multivendor Configurations -
Fluid, services-based storage networks allow for easy migration of storage services across host, fabric, and subsystem layers. -
Conventional view of competition focused within each layer. -
New competition is across each layer where host, fabric, and subsystem will compete to offer value-added services and a broader product portfolio. -
Users can balance both within and across layers. |
