QLogic 10000 Series Mt. Rainier Technology Accelerates the Enterprise - Manual (Page 7)

SSG-WP12004C SN0430914-00 rev. C 11/12 7
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cache coherence, enables adoption of server-based SSD caching as a
standard configuration. Because the caches are server-based, with proper
configuration they can take advantage of the abundant available bandwidth
at the edges of storage networks, allowing them to avoid the primary
sources of network latency: congestion and resource contention.
Managing Mt. Rainier Clusters
all Mt. rainier configuration, management, and data collection
communication takes place in-band on the existing storage network; no
additional connectivity or configuration is required. QLogic provides a Web
console, as well as scriptable command line and server virtualization plug-
in management tools.
Common management tasks, such as creating a Mt. rainier cluster,
adding or removing cluster members, configuring cache parameters,
and configuring SSD data LUNs are easily accomplished by running the
appropriate wizards within the QLogic QConvergeConsole
® (QCC) or an
environment-specific plug-in. Optionally, the scriptable host command line
interface (hCLi) may also be used to perform any operation.
Standard management tools provide advanced operations to enable cluster
maintenance while maintaining continuous availability. For instance, if a
server with a cluster member needs to be taken down for maintenance,
all of its SSD data LUNs, SaN LUN caching, and mirroring responsibilities
can be seamlessly migrated to other cluster members. When the server is
back online, the SSD data LUNs, caching, and mirroring responsibilities can
optionally be migrated back.
Configuration
the only topological requirement for establishing a cache adapter cluster is
that all members of that cluster must be able to “see” each other over two
independent storage network fabrics, as illustrated in Figure 10.
Figure 10. Storage Acceleration Cluster with All Mt. Rainiers Attached
to the Same Edge Switch
For Fibre Channel SaNs, all cluster members must be zoned together
in each fabric to which they are attached. to optimize performance, the
recommended best practice is to configure clusters with all members
connected to the same pair of top-of-rack or end-of-row switches. this
topology is a good match for a rack- or row-oriented storage network
layout, providing both direct and indirect system performance benefits.
intra-cluster communication takes advantage of the availability of excess
bandwidth at the storage network edge to optimize storage accelerator
cluster performance. Much of the high-load storage i/O traffic is removed
from the network core, thus benefiting other, non-accelerated storage i/O
requirements.
Integration Tools
to support automation and integration with third-party tools, QLogic
provides full access to all cache configuration and policy options through
the host CLi, as well as an aPi.
host Command Line interface (hCLi)
any configuration, management, or data-collection task supported by
QConvergeConsole can also be accomplished with the hCLi and may
optionally be scripted. For example, if you are using write-back caching—
when working with network storage that supports LUN snapshots or
cloning—to create point-in-time images (for example, for creating
consistent backups), you must ensure that the write cache is flushed before
taking the snapshot or clone. to perform flushing, insert hCLi cache flush
commands in the snapshot or cloning pre-processing scripts. Similarly,
when mounting a snapshot or clone (for example, in a rollback operation) to
Mt. rainier-enabled servers, hCLi commands may be scripted to first flush
the cache (if write-back is enabled), and then invalidate the cache for the
affected LUNs before proceeding with the rollback volume mount.
the hCLi also provides advanced SSD data LUN and SaN LUN caching
commands that automate provisioning, decommissioning, and policy
changes. For instance, based on knowledge of application processing
cycles, you may need to modify write caching parameters. a LUN involved
in decision support nominally has low and “bursty” write activity, and
would benefit from a write-back caching policy. however, when such LUNs
are refreshed (for example, during periodic extract-transform-Load [etL]
activities), the profile changes to heavy write, and therefore write-back
should be disabled by inserting the hCLi cache policy commands into the
etL control scripting.
Mt. rainier aPi
third-party developers and end-users who write custom applications can
have direct access to all SSD data LUN and SaN LUN caching configuration,
management, and data collection facilities of Mt. rainier clusters by means
of the QLogic Mt. rainier aPi. in addition to the capabilities described for