March 2013
Dell EqualLogic Configuration Guide v14.1
1-7
Controller
type
Faceplate
Network
interfaces
Storage
type
Notes
Type 9
2 x 1GbaseT
1 x 10/100Mb
mgt
SAS
SATA
2
nd
generation
PS4000
2GB Cache
Cannot mix SAS and
SATA drives in same
array
Type 10
2 x 10GB
SFP+
1 x 10/100Mb
mgt
SAS
SATA
SSD
10Gb Ethernet
PS6010 – PS6510
2GB Cache
1.3.2
Controller redundancy in all models prior to PS4100/PS6100
Each array can be configured with either a single controller, or dual redundant controllers. The single
controller configuration will provide the same level of I/O performance as a dual controller
configuration. The dual controller configuration provides for redundancy. Redundant controllers will
prevent volume connections between hosts and SAN from being dropped in the event of an active
controller failure.
The
Active Controller
is the controller which is processing all disk and network I/O operations for the
array. A second controller in dual controller configurations will always be in a “passive” operating
mode. In this mode, the secondary controller will exhibit the following characteristics:
•
Each of its Ethernet ports are electrically inactive (active lights are off)
•
The passive controller cache mirrors the cache of the active controller.
1.3.3
Controller failover behavior in all models prior to
PS4100/PS6100
To support redundant controller fail over, each Ethernet port on the active controller that is connected
to the SAN must have its corresponding port on the passive controller also connected to the same
SAN network. In the event of a controller failure, the passive controller will immediately activate and
continue to process all data requests to the array. The following changes occur during fail over:
•
The backup controller automatically enables each of the corresponding Ethernet ports that
were enabled on the failed primary controller
•
The IP addresses that were assigned to each of the failed controller Ethernet ports are
reassigned to the corresponding ports on the second controller.
A link failure on one or more of the Ethernet ports on the active controller does not constitute a
controller failure. For this reason, it is important to ensure that ports from each controller are
connected to at least two different switches. This will prevent a switch failure from also disabling all
paths between a host and its connected volumes.
It is also critical that port connections for both controllers are configured so that the corresponding
ports on each controller are connected to the SAN. If port 0 on the active controller is the only port
