Table 18 Cabling principles (Brick order in strings) (continued)
Cabling principle
Applicability
Note: The practice of adding Bricks to the last Brick on the string
is recommended for non-disruptive upgrades and for existing
customer systems. The goal in the field must be to perform non-
disruptive upgrades, if at all possible.
Table 19: Cabling principles (Brick balance in strings)
defines the balance that
must be maintained between the various Brick types in the Brick strings within a
Pillar Axiom 600 system.
Table 19 Cabling principles (Brick balance in strings)
Cabling principle
Applicability
A string may contain up to eight Bricks. (FC Expansion Bricks
(version 1) are not included in this number)
ALL
When additional Bricks are added or when SSF performance
issues occur, it may be necessary to rearrange the Bricks
between strings to better balance the system.
NEW
Bricks in a Pillar Axiom 600 system can follow a heuristic balance
or a numerical balance defined by Pillar manufacturing practices.
ALL
A numerical balance allocates Bricks to strings uniformly without
regard to the type of Pillar Brick. The longest and shortest Brick
strings differ by at most one Brick, with the exception of
FC Expansion Bricks.
NEW
Some rules have been developed to achieve a heuristic balance
on Brick strings. The heuristic balance on Brick strings helps to
optimize performance on larger systems with mixed Brick types.
Brick strings are balanced on the basis of load factors allocated to
the different Brick types as follows:
● SATA Brick: Load factor 1
● FC RAID Brick: Load factor 2
● SSD Brick: Load factor 4
Version 1 and version 2 of all Brick types are allocated the same
load factor.
FIELD
Chapter 4 Connect Data Cables
Cabling Practices for the Pillar Axiom 600 System
92
