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The industry-leading data and service availability provided by Membrain is a key benefit valued
by its users. Some SanDisk customers use Membrain as their sole data repository, without a
database as the primary data store. For these customers, the comprehensive data and service
availability of Membrain is critical. For example, a SanDisk telecom customer stores all the
address books for users of mobile and cable services in Membrain servers. They configure the
Membrain nodes with transparent replication and automatic failover, and they use the Membrain
Backup/Restore facility for periodic backups for recovery from disasters and less catastrophic
forms of data corruption, such as those caused by client application defects.
The rest of this white paper describes: Memcached; the architecture of Membrain; the key capa-
bilities of Membrain; and use cases for Membrain. We conclude with a summary of key points.
Memcached Overview
Memcached is a distributed key-value caching is widely used in high-traffic Web sites.
Memcached is generic, providing caching for arbitrary chunks of data such as results from
database calls or page renderings. Memcached is proliferating because of its effectiveness at
off-loading database and application servers, with dramatic improvement in Web site response
time and throughput.
Memcached is based on a standard client/server protocol which is maintained by the
Memcached open-source community, which also maintains various client libraries, a reference
server implementation, and management, administrative and compliance tools.
Membrain Architecture
Membrain seamlessly integrates the Memcached protocol with the SanDisk Operating
Environment (SOE) (described later in this white paper) and the underlying hardware platform
to provide superior enterprise caching and key-value store performance, capabilities, and
features.
Membrain is based on a system architecture that holistically manages state-of-the-art, enter-
prise-class flash memory, multi-core processors, DRAM, and high-performance networking to
optimize the performance, availability, and TCO of the Memcached client/server protocol. This
architecture was created based on extensive workload characterization, system modeling, and
optimization. The result is a highly optimized cache/key value store that effectively harnesses
these powerful technologies to provide a solution that is scalable, smart, cost-effective, and
green. Web facing datacenters can now leverage the advanced technology of SanDisk’s tightly
integrated solution to quickly and easily manage data growth, decrease business complexity,
and cut TCO.
Hardware Platform
Membrain runs standard x86 servers with flash memory. The recommended hardware platform is:
Dell, HP, or IBM x86 server or blade with at least 64GB of DRAM
PCI-e enterprise flash memory or at least 5 SATA/SAS SSDs
A single 10Gb or multiple 1-Gb Ethernet ports.
The SanDisk Operating Environment (SOE)
The SOE unlocks the full potential of the hardware by optimizing the utilization of all the
available physical resources across a broad spectrum of workloads. It enables full utilization
and linear scalability of multi-core processors, intelligently manages caching from DRAM to
flash, delivers highly parallel read- and write-optimized flash memory access, and manages high
performance replication of cached data between Membrain servers.
The SOE consists of the Memcached client/server protocol layer, SanDisk data fabric, the flash
management subsystem, flash and network management, and administration, as shown in
Figure 1 on the following page.
