C-13
Appendix C SAS-933EL Backplane Specifications
SAS HBA
SAS HBA
Dual Host Bus Adapter
In a dual host bus configuration, the
backplane connects to two Host Bus
Adapters.
Dual Host Bus Adapter
Failover
If the expander or data path in Port A
fails, the system will automatically fail
over to Port B. This maintains a full
connection to all drives.
SEC_J2
SEC_J1
SEC_J0
PRI_J2
PRI_J1
B3
B2
B1
A3
A2
A1
PRI_J2
PRI_J1
PRI_J0
PRI_EEPROM
A3
A2
A1
Port A
Expander 1
Port B
Expander 2
SAS HBA
SAS HBA
SEC_J2
SEC_J1
SEC_J0
PRI_J2
PRI_J1
B3
B2
B1
A3
A2
A1
PRI_J2
PRI_J1
PRI_J0
PRI_EEPROM
A3
A2
A1
Port A
Expander 1
Port B
Expander 2
C-11 Failover with RAID Cards and Multiple HBAs
The SAS-933EL backplane may be configured for failover with multiple HBAs using
either RAID controllers or HBAs to acheive failover protection.
RAID Controllers:
If RAID controllers are used, then the failover is accomplished
through port failover on the same RAID card.
HBAs: If multiple HBAs are used to achieve failover protection and load balancing,
Linux MPIO software must be installed and correctly
configured to perform the
load balancing and failover tasks.
IMPORTANT: For RAID controllers, redundancy is achieved
through port failover. For multiple HBAs MPIO software is
required to achieve failover protection.
!
Figure C-8: Failover with Dual HBAs