Datacenter Storage: Doing More With Less

In the recent years, there has been an increase in the number of threats
like terrorist attacks, power outages and the hurricane and tornado season,
which have only exacerbated the challenges facing datacenters. While priorities
may change over time, one remains constant: The need to do more with less

The datacenter provides far more than just the tech nology aspect of a
business. But the average datacenter has grown extremely complex. New
technologies, fast growth, acquisitions, the online data explosion, and
increased security concerns have driven complexity up and utilization rates
down.

There are eight key trends and challenges that impact datacenters:
Connectivity, tiered storage management, thin provisioning, storage system
resiliency, application availability, unified storage, security, and integrated
data management.

Organizations that have higher revenue and are heavily dependent on online
systems, have the highest potential loss of revenue (up to $2 million per hour,
or $500 per employee) from application and network outages. The storage trends,
challenges, and solutions outlined below in a two-part article will help
solution providers catering to data centers to plan and adapt their client's
storage resources and policies.

Connectivity

Based on industry data from Gartner Group, the growth for fiber channel (FC)
slows, but it will still remain the dominant storage network technology for at
least the next five years, even though Internet Small Computer System Interface
(iSCSI) over Ethernet will restrain its growth. Continued backward compatibility
and the increase in speed (4GB, 8GB) continue to characterize FC technology for
the datacenter.

Ethernet-based iSCSI represents the biggest challenge to FC dominance and
10GbE helps to narrow the gap. InfiniBand (IBA) offers a low-cost switching
technology, but it is not a mature storage networking technology and only a few
vendors offer native IBA storage. Serial-attached SCSI (SAS) offers a low-cost
alternative to FC for low-to-midrange direct-attached storage, server/storage
(DAS) cluster environments, and, potentially in the future, small SANs, but will
not impact FC in the datacenter.

Tiered storage management

Organizations need ways to enhance storage capacity utilization and optimize
storage costs based on the value of data to the organization. By implementing
tiers of storage within data­centers, organizations can overcome some key data
management challenges such as increased storage requirements placed on primary
(expensive) storage while secondary storage remains underutilized, inability to
effectively place data on different types of storage based on its relative
business value, and the high cost of backup in the absence of appropriate
classification of data. This often results in excess data protection for data
that is not mission critical.

Some key deterrents to implementing tiers of storage include:

• High user downtime resulting from both tedious data migration procedures
  and long restore windows for archived data
• Significant administrative effort in restoring user access to migrated
  data
• Lack of solutions that can migrate data across hete­rogeneous storage
  platforms
• Lack of centralized manage­ment of distributed data to reduce
  administrative complexity
• Inability to organize data intelligently and present it to users logically

Solution: A data manage­ment solution needs to overcome these limitations to
deliver a simple yet powerful solution to implement tiers of storage across
multiple storage systems, independent of their location or performance
characteristics.

A tiered storage solution for the data center should provide:

• High level of automation
• Centralized management of heterogeneous storage
• Policy-based migration of data across storage tiers
• Non-disruptive data movement
• Business view of data
• independent of physical storage tiers

Thin provisioning

Datacenter IT managers and storage administrators routinely report using
just 30 to 40 percent of their total disk capacity. Whether the problem stems
from a direct attached storage infrastructure with its inherent islands of
stranded capacity or inefficient and inflexible data management software,
utilization won't improve unless the storage architecture is improved.

Solution: The first step in the implementation of any storage system is the
allocation of space to servers and applications. Most storage systems require
the storage administrator to pre-allocate specific physical disk space to
applications and once allocated, that space is no longer available (free) to be
used by other applications that may need it.

The problem is that in the early stages of deployment, the storage
administrator seldom knows the exact requirements of users and applications, and
most administrators have no way to assign storage space to applications without
'locking in' specific disk drives to volumes and LUNs.

Using the same example, the system administrator provisions 500GB to the
application with only 100GB of actual data. With thin provisioning, the unused
400GB is still available for other applications. This approach allows the
application to grow transparently and at the same time ensure that capacity is
not wasted.

Thin provisioning is essentially just-in-time storage. The application thinks
it has 500GB of storage, but the storage system only gives it the capacity as it
needs it. The rest of it stays in the pool and system administrators can set
thresholds to be alerted when to add more disks into the storage pool.

Storage system resilience

Enterprise datacenters must provide high levels of application availability
and consistent data integrity to support business-critical applications around
the world. Datacenter managers continually wrestle with the challenges of
avoiding unplanned downtime to ensure application data is available and of
avoiding data corruption to ensure that application data is correct and up to
date.

Two industry trends-datacenter storage consolidation and the widespread
adoption of larger-capacity storage-make high availability a more urgent
priority for storage and IT managers. With consolidation, even higher
availability is required as more data and applications are at risk.

At the same time, increased adoption of SATA storage with larger disk
capacities increases the risk and probability of failures. Productivity growth,
increased global competition, and stringent regulatory requirements make
additional demands.

Solution: To protect against business interruption, storage resiliency
should be built into every aspect of the storage solution. True storage
resiliency has two aspects and storage architecture needs to provide both: (1)
preventing errors and system failures from happening by means of early detection
and self-healing processes and (2) recovering quickly and unobtrusively from
errors and system failures when they do happen.

A solution provider's solution should include tools to predict and fix disk
drive faults before they happen, protect against all forms of double disk
failure cost-effectively and with minimal impact to performance, maintain data
availability in spite of triple disk, enclosure, and storage loop failures, and
support synchronous and asynchronous replication, clustered failover (local and
remote), and fully redundant, fault-tolerant systems.

Mike McNamara

(The author is Product Marketing Manager, Network Appliance)