High Availability / Dual Domain Information - HP 634041-006 Deployment Manual

4 High availability / dual domain information

HP External SAS BladeSystem Solutions provide high availability, offering c-Class BladeSystem
users full connectivity to External SAS storage by using the following redundant hardware
components:
Two controllers in each external shared SAS storage enclosure
Two I/O modules in each MDS600 or D6000 storage enclosure drawer (four per enclosure)
or D2600/D2700 storage enclosure.
Two SAS BL Switches in the BladeSystem c-Class enclosure interconnect row
One or more P71 1m, P712m, or P721m/P731m controllers in each server
Dual-ported SAS hard drives in the external SAS storage enclosures
Redundant power supplies and fans in the BladeSystem c-Class enclosures and external SAS
storage enclosures.
Using redundant components ensures high availability. If any component in the path between the
server and the storage fails, management software will automatically fail over all I/O to the alternate
path.
Although single-controller shared SAS external storage enclosures and single I/O module zoned
SAS external storage enclosures are supported for use in single-domain environments, the
dual-controller/dual I/O module models are required in high availability environments. With two
controllers/two I/O modules, high availability is ensured if one of the controllers/I/O modules
fails. During a failover event, all processing is performed by the remaining controller/I/O module,
with no interruption to the flow of data.
When configuring the storage, the storage enclosures offer a variety of RAID levels, allowing a
user-selected level of performance and fault tolerance. For more information about RAID levels and
configuring the MSA 2040 SAS or P2000 G3 SAS MSA storage, see the HP MSA 2040: Best
Practices white paper at http://www.hp.com/go/msa2040. For more information about RAID
levels and configuring the or P2000 G3 SAS MSA storage, see the or HP MSA2000 G1, MSA
2000 G2, and P2000 G3 MSA Best Practices white paper at
(under Resource Library).
NOTE: HP SSA can perform all the functions that HP ACU can, along with added features not
available with ACU. For more information, see the HP Smart Storage Administrator User Guide.
For more information about RAID levels and configuring the D2600/D2700, MDS600, or D6000
storage, see the Configuring Arrays on Smart Array Controllers Reference Guide, at
h18000.www1.hp.com/products/servers/proliantstorage/software-management/acumatrix/.
Although beyond the scope of this document, clustering is supported in BladeSystem environments,
providing another level of fault tolerance. For more information about clustering support see the
QuickSpecs for your storage enclosure.
http://www.hp.com/go/P2000
http://
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