Which operation is performed by a scale-out NAS when it receives a large write I/O from its
clients?

A.
I/O is striped across multiple nodes for processing

B.
I/O is sent to the high performance node in the cluster for processing

C.
A new node is dynamically added to the cluster to process the I/O

D.
I/O is sent to the high storage capacity node in the cluster for processing

Explanation:
NAS Implementation – Scale-out NAS
The scale-out NAS implementation pools multiple nodes together in a cluster. A node may consist
of either the NAS head or storage or both.
The cluster performs the NAS operation as a single entity.
A scale-out NAS provides the capability to scale its resources by simply adding nodes to a
clustered NAS architecture. The cluster works as a single NAS device and is managed centrally.
Nodes can be added to the cluster, when more performance or more capacity is needed, without
causing any downtime. Scale-out NAS provides the flexibility to use many nodes of moderate
performance and availability characteristics to produce a total system that has better aggregate
performance and availability. It also provides ease of use, low cost, and theoretically unlimited
scalability.
Scale-out NAS creates a single file system that runs on all nodes in the cluster. All information is
shared among nodes, so the entire file system is accessible by clients connecting to any node in
the cluster. Scale-out NAS stripes data across all nodes in a cluster along with mirror or parity
protection. As data is sent from clients to the cluster, the data is divided and allocated to different
nodes in parallel. When a client sends a request to read a file, the scale-out NAS retrieves the
appropriate blocks from multiple nodes, recombines the blocks into a file, and presents the file to
the client. As nodes are added, the file system grows dynamically and data is evenly distributed to
every node. Each node added to the cluster increases the aggregate storage, memory, CPU, and
network capacity. Hence, cluster performance also increases.
EMC E10-001 Student Resource Guide. Module 7: Network-Attached Storage (NAS)