HP StorageWorks 8000 NAS - Manual (Page 4)

hp solution overview
Data integrity, reliability, scalability and high performance are top priorities in any database
implementation. The use of Network Attached Storage (NAS) devices to store database data files has
traditionally been discouraged because it was thought that network instability and perceived vulnerabilities
of non-local storage posed too great of a potential risk to data integrity and would greatly reduce system
performance. However, networking and storage technologies have matured and improved to a point
where what was once looked upon with suspicion is now taken for granted. While there are exceptions, it
is certainly no longer the rule that networks are too unstable for mission critical use. In fact, it is now almost
a given that in an office of any size, there will be some form of a computer network and probably some
form of non-local storage such as a file server. Whether this network consists of a couple of desktop
computers, a file server and a shared printer, or whether this network consists of thousands of systems
spanning cities/countries/continents, networks and some form of non-local storage are in widespread use
today. As network technologies have matured and improved, so have the protocols that utilize the network
topologies. At all levels, network protocols have become more robust, more efficient, and have helped to
create a more stable network infrastructure. Advances in storage technology, with high capacity hard
drives, fail over and high availability RAID Arrays, improved management and access techniques (to
mention a few) have also helped to reduce concerns about data integrity and storage performance. These
advances have opened the door for the use of non-local storage, specifically NAS, for many applications,
one of which is to store database data files. Additionally, and of growing importance, is the need for a
scalable solution that does not require system downtime in order to increase available storage. The HP
NAS 8000 has been engineered to provide a complete NAS solution providing data integrity, reliability,
high performance, scalability and ease of management, as well as heterogeneous file access.
The HP NAS 8000 has been tested with the Oracle database engine on various Operating System
platforms, as well as undergoing Oracle Storage Compatibility testing (OSCP). The OSCP test suit and the
testing process of the NAS 8000 are described in the OSCP test report white paper (see above for home
page link).
The NAS 8000 uses state of the art HP technologies such as a special optimized operating system for fast
and efficient data access, an easy to use management GUI, HP VA array with HP AutoRAID tm for data
protection/availability and is scalable up to 7.7 terabytes of data (in the non-clustered configuration). The
NAS 8000 utilizes either the HP Virtual Array 7100 (VA 7100), or the HP Virtual Array 7400 (VA 7400)
as the storage subsystem. The NAS 8000 can be connected to the VA 7xxx Array either through direct
connections, or through a SAN. The VA 7xxx storage subsystem is designed to provide a very high level of
data protection and reliability by utilizing dual array controllers that provide redundant and concurrent
access to array storage, and implement HP AutoRAID tm technology. The dual controllers provide parallel
data access pathways for all data located in the storage subsystem; in the unlikely event that one controller
should fail, the other controller will provide access to all data in the storage subsystem. Each controller
contains a battery to protect the contents of the non-volatile ram (NVRAM) for at least three days in the
event of a power failure. The dual controllers also provide NVRAM “mirroring” through special hardware
that guarantees that the mirrors are always in sync. The mirrored NVRAM provides extremely safe and
reliable storage for system configuration information and for write cache. This massive redundancy within
the VA 7xxx ensures that a single failure will not result in data loss and usually will not cause a service
interruption. Even if a catastrophic failure (such as a total power failure for more than 3 days) were to
cause a loss of the NVRAM contents, the system storage configuration and storage maps can be recovered.
At default/factory settings, the write cache is flushed to the hard drives at a maximum of every four
seconds. The actual time that data is staged in write cache depends upon system configuration and
utilization. The possibility of a single failure in the NVRAM is extremely small and the VA 7xxx should not
suffer any loss of. The possibility of a dual NVRAM failure resulting in data loss is significantly smaller. For
performance, data protection and data availability descriptions please refer to the HP virtual array VA
7100 and 7400 user and service guide located off of the VA 7400 home page (see above for home page
link).
The NAS 8000 makes extensive use of the concept of ‘virtualizing’ storage. This essentially means that the
storage subsystem is able to take all of its physical disk storage and make it appear as a pool of storage
that can be ‘partitioned’/divided up by the NAS 8000 administrator as each environment requires. One
task that traditionally has been assigned to the database administrator is planning the storage layout for a
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