Fabric Design Data Availability; Calculating For Data Availability Levels - HP StorageWorks 4000/6000/8000 - Enterprise Virtual Arrays Reference Manual

Table 8 indicates data availability and supported topologies for each level.
Table 8 Fabric design data availability
Fabric design
Level 1: single connectivity fabric
Level 2: single resilient fabric
Level 3: single resilient fabric with
multiple device paths
Level 4: multiple fabrics and device
paths (NSPOF)
You can add fabrics to increase the number of available ports.
each data availability level.
Table 9 Calculating for data availability levels
Fabric design
Level 1: single connectivity fabric
Level 2: single resilient fabric
Level 3: single resilient fabric with
multiple device paths
Level 4: multiple fabrics and
device paths (NSPOF)
1
x is the cost of a single connectivity fabric.
2
n is the total number of ports for servers and storage systems.
3
May require use of zoning to define a minimum of two data paths in a single fabric (operating system dependent).
Availability level
No redundancy
Medium
High
Highest
Hardware cost
1
x
x + additional ISLs
x + additional ISLs + additional
HBAs
x + additional ISLs + additional
HBAs + additional switches
SAN topologies
Single switch or multiple switches with single
ISL
Cascaded with two ISLs, meshed, ring, and
core-edge
All
All
Table 9 lists the cost calculations for
Number of available ports
# ports = n – number of ISL ports
# ports = n – number of ISL ports
# ports = n – number of ISL ports –
additional HBA ports
# ports = 2n – number of ISL ports
– additional HBA ports
SAN Design Reference Guide
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