Managing
storage
Managing the data, and the devices on which it is stored, has been
accomplished on a server-by-server basis. Typically, storage capacity
and infrastructure are purchased and added to individual systems.
Alternatives exist. Compaq offers storage subsystems that allow
consolidation of data from multiple heterogeneous servers within
a single cabinet and allow each cabinet to be managed as a storage
entity. While this approach is useful today, a more complete model
is needed to satisfy expanding business needs.
Another extremely
important problem is protecting data. Today's RAID subsystems and
hardware redundancy help protect against loss of individual disks,
power supplies or array controllers. Properly administered backup
policies and attendant hardware and software can protect against
human errors, software errors and other loss.
A major stumbling
block today is the time it takes to restore data. This time increases
with the volume of data and can be only partially reduced with substantial
hardware and software expenditures. ENSA's instantaneous data replication
provides the means to unobtrusively backup and quickly restore data.
A
new approach
Unlike other approaches to network storage, such as storage area
networks and network-attached storage, ENSA behaves organically
while providing virtually unlimited capacity. The architecture supplies
storage as a utility, similar to conventional electric and water
utilities. Raw capacity is prepared by storage virtualization engines
for distribution to the application servers. It is then delivered,
over a distribution fabric to the application servers on demand.
Distribution is both reliable and transparent to all applications
served.
ENSA incorporates
storage devices-components interfacing with application servers-linking
infrastructures and tools which administer the entire environment.
These elements communicate and cooperate to solve data storage and
management problems. This organic behavior is totally transparent.
Applications see only a reliable, available utility that conveniently
delivers the storage they need on demand.
Building
a Framework
As computing environments become richer and more scattered, storage
solutions must follow suit. ENSA's philosophical approach is to
distribute physical storage throughout the enterprise as needed,
affording central management as appropriate. To satisfy ongoing
computing needs, a network storage solution must incorporate several
key attributes, such as:
- Consistent,
reliable access to data, regardless of the status of individual
components anywhere in the storage system.
- Similar access
to data for heterogeneous operating systems.
- Performance
required by applications whose data is stored on the system.
- Monitoring
capabilities that provide useful reports of factors such as storage
and performance utilization by applications.
- Unified,
policy-driven, automated solutions to manage physical storage
in increasingly distributed and complex environments.
ENSA addresses
these needs with storage virtualization, dynamic scalability and
simplified management tools within a framework that offers maximum
investment protection.
Storage
virtualization
ENSA creates a flexible, shared storage resource by applying storage
virtualization on a new scale. It allows vast amounts of physical
capacity to be pooled across the enterprise for presentation to
application servers wherever they may be. It virtualizes storage
capacity so that disks of different capacities and data protection
levels can be created from a set of physical disks. ENSA disks are
created from a pool distributed across the storage web, cluster
or cell, as needed by applications. RAID and other techniques are
applied to provide data protection. An ENSA disk can be accessed
by more than one server, and a server can access many ENSA disks
within normal operating system compatibilities.
Virtualization
occurs either within atomic units called storage cells, or among
storage cells bound into cooperating entities called storage clusters.
Storage clusters can span the same distances as conventional storage
area networks. ENSA extends virtualization to a global scale with
the storage web. The storage web creates a single manageable entity
from a cooperating collection of storage clusters. The latest interconnect
technologies provide high-speed throughput and delivery of storage
performance to the consuming servers. Storage cells, storage clusters,
and the storage web work harmoniously with direct-attached and other
forms of storage.
Dynamic
scalability
Unlike conventional disks, an ENSA disk's capacity is not limited
by the physical disk capacity in the storage pool. Instead, it is
designated a capacity appropriate for the application.
ENSA automatically
allocates physical storage capacity to individual applications until
its designated logical capacity is reached. This is based on the
amount of ENSA disk capacity actually used. ENSA continuously monitors
server capacity needs and projects capacity automatically from the
storage pool. This means raw capacity provided to the pool can increase
the physical capacity of an ENSA disk from the pool-dynamically
and transparently.
Since the physical
storage allocated by ENSA to its disks matches the actual need of
the server in real time, as one server's needs decline the physical
storage can be automatically recovered and returned to the pool
for reallocation to other virtual volumes.
The distribution
and connectivity facilitated by ENSA allows addition of virtually
limitless capacity to the storage pool in any increment at any time.
This means vast ENSA disks can be created from significantly less
physical storage than they will ultimately contain. ENSA System
Managers merely need to be sure the pool has enough physical storage.
Extraneous software management tools that reveal capacity allocation
problems are no longer needed.
Investment
protection
ENSA is designed to serve enterprise needs well into the future.
Because of its farsighted approach, ENSA can take advantage of new
technologies as they become practical to deploy. In the StorageWorks
tradition, ENSA's evolution will be accomplished with maximum protection
of existing storage investments.
ENSA provides
evolutionary stages of technology deployment leading to an ultimate
vision. ENSA allows environments to develop at their own pace from
today's foundation. The evolution begins with today's Ultra SCSI
components and then grows through conventional SANs. The next stage
expands to encompass conventional enterprise networks. Finally,
the overall ENSA vision is realized as the enterprise storage networks
are united within the storage web. This allows for the planned implementation
of the ENSA vision, with unprecedented level of investment protection,
even in the early stages of deployment.
A key feature
is that the new network storage environment is carefully designed
to coexist harmoniously with existing direct-attached and network-attached
storage. This means ENSA can be deployed incrementally as business
needs change.
Business
success
The world of enterprise computing is changing rapidly as businesses
become dependent on information-and the knowledge derived from it-for
their continued success. This is driving explosive growth and complexity
in storage as vendors strive to satisfy the demand for storage.
ENSA is designed
to evolve with the enterprise into the future. This unified vision
encompasses not only storage hardware and software, and the functionality
that integrates it, but also extends to the services and support
required to design, install and maintain it.
Courtesy:
Compaq Computer Corp