Specifications

Escala Tower PL & S, E, T System Hardware
Chapter 3: External Storage and SAN Subsystems 75/116
9es3s1c3.doc
Rev 5.9
02/12/2003
Cost reduction:
The cost of storage systems depends on the cost of the disks, but also on the cost of
the enclosure and of the management software. In a private storage architecture, it
is usually mandatory to buy lot of small or medium size enclosures. With the SAN
architecture, it is possible to reduce the number of enclosures, thanks to the
capability of storage sharing through the network. Furthermore, the disk space in
the enclosures can also be shared. Another factor of cost reduction arises with the
performance of the high-speed network that allow to use larger storage systems,
which are usually less expensive (per GB) than several smaller systems.
Easy
administration:
The separation of servers and storage resources allows to recentralize, consolidate,
and homogenize the storage systems and their management applications. Storage
administrators do not need to be trained for any server operating system and
management software. Management is simplified (less variety and number of
equipment, less tools, less consoles), and consolidated (aggregation of information
from several storage systems). Failure detection, prevention and trend analysis is
much easier, due to the lower number of storage systems to monitor.
High security and
availability:
The SAN improves the availability and security of the storage. The SAN offers a
meshed infrastructure with multiple paths. Redundant interfaces for servers and
storage systems provide highly available data path between servers and storage.
Thanks to the networked access, the storage remains available even in case of
server failures. The cost reduction generated by the storage concentration facilitates
the deployment of RAID solutions, which can be used by any server. The systems
themselves can be more secure, with internal high availability features (hot plug,
redundancy). The reduced number of storage systems to manage facilitates backup
operations.
Improved
performance:
The SAN improves the performance in various ways:
•
Any application server can directly be connected to the storage systems at a
(multi-) gigabit speed. Compared to today network storage solutions based on
protocols operating on LANs (NFS, DFS, and SMB), the data access is highly
improved.
•
Data can be shared between hosts, avoiding unnecessary copies.
•
The use of high-end storage systems, with a high internal bandwidth, larger
read and write caches and efficient processing engines boosts the performance.
Quick evolution
capability:
The storage concentration enables a very quick adaptation to the evolution of the
information processing. The storage allocation is extremely flexible and scaleable.
Administrators can migrate applications from servers to servers, add or remove
servers without any impact on the data: no need to move data from a storage system
to another, no need to add disks, ... The data remain at their location, only routing
and access rights must be modified. Administrators can add storage without
stopping application servers.