Device Deduplication

Without deduplication, a single physical device is modeled as multiple device items when it is discovered from multiple sources (SNMP, camm, cavna, or another source). Deduplication models a single device in capm.
capm350
Without deduplication, a single physical device is modeled as multiple device items when it is discovered from multiple sources (SNMP,
CA Mediation Manager
,
CA Virtual Network Assurance
, or another source). Deduplication models a single device in
CA Performance Management
.
The following general rules apply to deduplication. Exceptions to these rules are covered in the following sections.
  • CA Performance Management
    deduplicates devices only when they are in the same IP domain.
  • CA Performance Management
    successfully deduplicates devices regardless of discovery order.
  • When the deduplication criteria of a device (IP address, hostname, and so on) from one source matches an existing device item from another source,
    CA Performance Management
    does not create a new device item.  Instead, the same existing device item is used for both sources.
  • If attributes conflict and SNMP is a source, the attributes from SNMP take precedence.
SNMP Deduplication
New SNMP devices are not created in the following scenarios:
The primary IP address is the IP address that
CA Performance Management
uses to monitor a device. When a device is first discovered with the IP ranges discovery profile,
CA Performance Management
tries to use the IP address that maps to the hostname as the primary IP address.
  • The primary IP address matches an existing device. The existing device could be a
    CA Mediation Manager
    (CAMM) or
    CA Virtual Network Assurance
    (VNA) device with the same primary IP Address.
  • The hostname matches an existing device.
  • The primary IP address for a new device is in the IP address list of an existing device, and the primary IP address of the existing device is in the IP address list of the new device. If the primary IP address of the new device is listed as a single IP address in the discovery profile,
    sysName
    is verified. If the
    sysName
    of the new and existing device match, the new device is not created.
  • For devices that support the Device Unique Identifier metric family, the
    UniqueID
    matches an existing device.
SNMP and
CA Mediation Manager
Deduplication
CA Mediation Manager
(CAMM) monitors devices that do not support SNMP or provides metrics that are not accessible through SNMP polling. CAMM injects data into the Data Aggregator through one of the Data Collectors. When the CAMM device pack provides an IP address or hostname that matches another device in the system,
CA Performance Management
deduplicates the devices to a single item.
The following table illustrates that
CA Performance Management
deduplicates SNMP and CAMM devices when the IP address or hostname match:
IP Address Match
Hostname Match
Deduplication
Yes
Yes
Yes
Yes
No
Yes
No
Yes
Yes
No
No
No
To deduplicate devices by the IP address only, edit the discovery profile to exclude hostname. For more information, see Discovery Profiles.
The following criteria must be met for deduplication to occur:
  • Both the Data Collector and the CAMM Local Controller are in the same IP domain and poll the same device.
  • Either a matching IP address or a matching hostname is present in both SNMP and CAMM.
  • The CAMM device pack supports deduplication.
    Deduplication with CAMM devices occurs only for device packs that support deduplication. To determine which device packs support deduplication, see the information file of each device pack.
  • For multiple devices packs, the device names on each device pack match.
  • CAMM and SNMP discovery is successful.
CA Performance Management
deduplicates devices only when the Data Collector and CAMM Local Controller and are in the same IP domain. However, the Data Collector and CAMM Local Controller can reside on different servers. The following server configurations are supported:
  • Data Collector server for SNMP polling
  • Local Controller server for CAMM polling
  • Data Collector and Local Controller on the same server for SNMP and CAMM polling
If the combined workload is manageable, the CAMM Local Controller can be installed on the same server as the Data Collector for SNMP polling. However, ensure that your servers have enough capacity to continue operating with the normal SNMP polling load and the CAMM requirements.
For new installations, install the CAMM Local Controller on a Data Collector in the same IP domain with the devices that you want to monitor. Devices that are discovered through CAMM and through SNMP are deduplicated.
For existing installations, rediscover the devices with SNMP or CAMM. CAMM deduplication does not delete any existing duplicated device items. The historical data is still available on the existing device items. Historical data that was captured with the device model from an old IP domain still exists, but is unconnected to the newly reconciled device. We recommend that you delete or retire the device from the old IP domain to avoid double polling from CAMM. If the device from the old IP domain is not deleted, or the historical data is not aged out,
CA Performance Management
continues to have two devices.
CAMM components and SNMP components from the same Metric Family are not reconciled with each other. SNMP component discovery is delayed until the next change detection. An error occurs when all the following conditions are true:
  • SNMP and CAMM polled devices in the same IP domain.
  • The SNMP and CAMM devices were polled by the same Data Collector.
  • The SNMP and CAMM device packs contribute to the same Metric Family.
  • One of the two contributors (CAMM or SNMP) have late arriving data (greater than 30 minutes after the rollup period ends). Late arriving data is more likely to happen with CAMM data, especially with a 15-minute polling interval.
When the load on the Data Collectors is rebalanced, CAMM and VNA devices are not rebalanced. Therefore, deduplicated SNMP, CAMM, and VNA devices are not rebalanced. For more information, see Rebalance the Load on Data Collector.