Dell DX6004S DX Object Storage Getting Started Guide - Page 20

power costs of the additional nodes. For more information about sleepAfter, wakeAfter, and archiveMode settings, see the node configuration appendix in the DX Object Storage Administration Guide. 3.6. Proactive Power Conservation In addition to the power savings gained from the adaptive power conservation feature, administrators may need the ability to proactively reduce the power consumption peak and flatten the power spectrum consumption of the grid where power caps are required for either budgetary or compliance reasons. To support this use case, DX Storage allows administrators to optionally set the power cap for the cluster to a percentage of the maximum potential power consumption via either the admin console Settings pop-up or SNMP. It is highly likely that the power cap mode will result in some performance degradation so administrators should be aware of the potential impact to throughput prior to setting the power cap to anything lower than 100%. Note this feature is currently supported only on select Dell hardware. Note If the power cap percentage is changed using SNMP or the Admin Console and the corresponding cluster settings UUID is not updated in DX Storage configuration, the admin console and SNMP may get out of sync with the actual node state, as the power cap is preserved across reboots even if the cluster settings UUID is not persisted. 3.7. Local Area Replication Using Subclusters Local area replication (LAR) allows you to create logical separations in a DX Storage cluster to define storage distribution strategies. These logical separations change the normal behavior of the cluster so that DX Storage attempts to create the greatest logical spread between a stream's replicas by moving them into separate subclusters. If your cluster boots from a CSN, contact your support representative for instructions on manually configuring subclusters because the CSN Console does not currently support this. Examples where LAR subclusters are useful: • Splitting a cluster based on location (data cabinet, building wing) • Grouping nodes based on common infrastructure (network, power) An example of splitting a cluster based on location is a company that has data centers in separate wings of their building and wishes to have copies of stored content exist in both wings in case of a partial building loss. A loss could be events like a fire, flooding, or air conditioning problems. Similar to location based separation, you might wish to split a cluster based on common infrastructure. Examples are grouping nodes by shared network switches, a common Power Distribution Unit (PDU), or a common electrical circuit with in a rack. The network connections between LAR subclusters must have the same speed and latency characteristics as the connections between the nodes. Additionally, all nodes must be in the same broadcast domain such that they are able to send data directly to all other nodes in the cluster and receive the multicast traffic sent from anywhere in the cluster. Warning Avoid frequent changes to the subcluster assignments for nodes. When nodes move to new subclusters, there is the potential for a lot of cluster activity while content is redistributed to account for the new subcluster assignments. Copyright © 2010 Caringo, Inc. All rights reserved 17 Version 5.0 December 2010