To plan the physical installation of the system in racks, use the
examples of rack installations to ensure that the required space and access are available. These
installations provide different installation scenarios and depict the guidelines for installing the
nodes in a rack.
Consider several factors before you install the nodes. Determine whether you are creating a new
system or if you are adding nodes to an existing system that is composed of older node models.
If you are creating a new system, you need to determine whether you are installing the nodes in a
single rack installation or a dual rack installation.
Considerations for single and dual rack installations
When you are determining whether to implement a single or dual rack installation, you need
consider all aspects of the data center that you are installing into. Consider the high availability
design for your overall storage environment. In single rack installations, all eight nodes are
installed into a single rack. In a dual rack, these nodes are split between two separate racks,
where A nodes are in one rack and B nodes are in the other.
If the data center has power redundancy attributes and your storage environment does not have
fully redundant components, a single rack implementation saves you costs associated with a dual
rack.
If the data center does not have sufficient power redundancy or it does not contain fully
redundant components, then the added cost of a dual rack design is justified. In this case, a dual
rack extends the level of high availability and redundancy of your overall storage environment.
Finally, if you are planning to add another system to the storage environment in the future, you
can reserve space in each rack in a dual rack installation for nodes that you plan to add.
Use the following guidelines to help you determine whether to install nodes into a single or dual
rack installation:
- Considerations for the data center
- If you are installing nodes into an existing data center, ensure that you understand the
following considerations that impact your installation:
- Redundant power capabilities
- Most data centers implement redundant power sufficient for the data protection and availability
if a power disruption occurs. However, data centers should have redundancy of the power to the rack,
such as power circuit panels and on-floor PDUs. It should also have power redundancy within the rack
such as dual power strips or in-rack PDUs. The data center should also have high availability power
structures if a data center-wide outage occurs.
- Fire protection systems
- Consider the fire protection systems, such as over head sprinkler systems and alarms that are in
place in the data center.
- Considerations for location and separation of storage components
- Each of the following storage components can have requirements that affect the choice between a
single and dual rack implementation:
- Backend storage
- If you are implementing a single system that is attached to a single backend storage device,
separating the system between two racks does not provide any additional advantages to the storage
environment. However, if you have multiple devices and the environment does have fully redundant
components, investing in a dual rack design can help add availability to the system.
- SAN switches
- If you installed pairs of switches in the same rack, it is not necessary to separate nodes
between two racks. If switches are installed separately in different rack, then installing the nodes
in separate racks provides consistency in implementation and provides redundancy if one of the
switches fails.
- Physical distance between components
- If you are implementing storage with multiple redundant devices that are separated across
multiple racks, ensure that these components have different power sources and are in different fire
protection zones. Otherwise, the storage environment can be compromised in a fire or power
disruption.
Considerations for selecting a rack
These nodes and their associated components can be installed into any IBM® or third-party rack. Use these guidelines to ensure that the best rack for
your needs is obtained:
- Considerations for the data center
- Consult with staff of the data center that you are installing the system to if they have
requirements for racks that are used throughout the data center. If there are specific requirements,
ensure that your rack meets those standards.
If they do not have requirements for racks, choose a
rack that has the same height of other racks within the data center, if possible.
- Consideration for rack size
- The default height for all models is 42 units high. Verify with data center personnel that
height clearances for the rack that you chose are adequate. Some data centers might require shorter
racks. Ensure that you also consider the space that is required for cabling, cabling managers, and
associated hardware, in addition to the nodes and components that are installed.