Deployment Guide

9 Dell EMC Networking OS10 Enterprise Edition Storage Overview
4 Storage benefits and limitations
The general benefits and limitations of each storage type are outlined in this section.
4.1 Direct attached storage
DAS limits the use of shared storage. The benefits of DAS is mainly cost. Cloud providers use a DAS solution
to deploy massive farms of storage servers and low-cost JBODs (just a bunch of disks) as an alternative to
large dedicated disk arrays. DAS includes disks internal to a physical server and external JBOD cabinets
attached to the server using a SAS cable. The DAS solution allows you to add low-cost storage easily.
4.2 Network attached storage
With NAS, data is stored as files and designed to interface with locally networked storage but provides more
structure in the form of file systems and files. File systems have natural limits that are based on the local
internal structures that are used to manage the file hierarchy and file access. The information within the
managed file hierarchy provides awareness of the content in the system, however, it is entirely localized to a
physical storage controller. By design, NAS systems are limited in scale and scope. Clustered NAS systems
extend the expandability of the technology, however, NAS has natural limits that are tied to physical
controllers, and to the central database that is used to track the file hierarchy and files.
The main benefits of NAS include:
• Scale-out capacity - The addition of more storage capacity to NAS is done by adding more hard disks.
You do not have to upgrade or replace existing servers, and new storage can be made available without
shutting down the network.
• Performance - Because NAS is dedicated to serving files, it removes the responsibility of file serving
from other networked devices. Also, since NAS is tuned to specific use cases (like big data or multimedia
storage), clients can expect better performance.
• Easy setup - NAS architectures are often delivered with simplified scripts, or even as appliances
preinstalled with a streamlined operating system. This configuration reduces the time that it takes to set it
up and manage the system.
• Accessibility - Every networked device has access to NAS.
• Data protection: NAS can be formatted to support replicated disks, a RAID, or erasure coding to ensure
data integrity.
4.3 Storage area network
Data is stored as blocks and designed as the most basic way to interface with storage over a dedicated local
network. SAN controls blocks of data in small logical volumes but has no context of what the data is. SAN
depends entirely on the application to organize, catalog, and structure the data. By design, SANs are limited
in scale, interfaces, and scope. SANs are typically higher in cost due to the dedicated network infrastructure.
The use of SSDs in a SAN array is functionally similar to traditional disk arrays. SSDs in a SAN array present
shared capacity to multiple hosts but with the inclusion of solid-state drives, optimized platforms reach high IO
points and low latency with shared resources.