Specifications

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Cisco TV CDS 2.5 ISA Software Configuration Guide
OL-24788-01
Chapter 1 Product Overview
Content Delivery System Architecture
Local Mirroring
Local mirroring defines the number of copies of each content object to maintain on the unique drives of
a single Vault. Local mirroring allows resiliency for a small installation (for example one Vault). Local
mirroring guards against a single drive failure, but does not protect against service interruption or
potential data loss in the event of a complete server failure.
Local mirroring is not configured by default, and is generally only used when there is a single Vault in
a system. Local mirroring is configured in the Configure > Server Level > Server Setup page with the
Vault Local Copies field, which corresponds to the tunable “vault local copy count” in CServer. Up to
four local copies are supported.
Mirroring within an Array
Mirroring within an array defines the number of copies of each content object in an array to maintain
across the Vaults within that array or site. Mirroring within an array guards against a single drive failure
or the failure of an entire server. The number of copies to maintain within that array is configurable in
the Configure > Server Level > Server Setup page with the Vault Mirror Copies field, which
corresponds to the tunable “vault mirror copies” in CServer. Up to 10 copies within an array are
supported.
Array Mirroring
Array Mirroring (from Vault Group to Vault Group) specifies that each content object on all of the Vaults
in one group has at least one copy on a Vault in the mirrored Vault Group. Array Mirroring is only
responsible for ensuring that a single copy of each content exists in the mirrored Vault Group. If more
than one copy of each content object is required within an array, Mirroring within an Array (not Array
Mirroring) is responsible for this task. Array Mirroring is configured in the Configure > Array Level >
Vault Redundancy Map page, which corresponds to the tunables “allow vault array mirroring” and
“vault array mirror” in CServer. Each Vault Group can have up to 3 mirrored Vault Groups configured.
Note Array Mirroring is part of the Vault Groups feature and is only available if Vault Groups is enabled on
the CDSM Setup page. For more information, see the “Vault Groups” section on page F-5.
Vault Server Resiliency
The Cisco TV CDS can handle the loss of an entire Vault server without impacting the subscriber. The
communication with the backoffice suite is performed by a Vault server that is designated as the Vault
master. If the Vault master fails, one of the remaining slave Vault servers in the Vault array transparently
takes over as the master. The remaining Vaults detect the loss of a Vault server, run a check of all stored
content, and regenerate redundant content that was affected by the lost Vault server. This regeneration
runs in the background, utilizing spare system bandwidth that is not consumed by subscriber load,
resulting in the shortest possible regeneration window possible without compromising performance to
the subscriber.
Vault Master
The Vault master, designated by a virtual IP address on its management interface, is used as the
representative of the Vault array to the backoffice and handles the ingest of new content.