Dell EqualLogic PS4210X EqualLogic Group Manager Administrator s Guide PS Seri - Page 248
About Replication Space, About Local Replication Reserve
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Figure 18. Centralized Replication About Replication Space Volume replication between partners requires space on both the primary group (the volume location) and the secondary group (the replica location). These space requirements are classified in the following way: • Local replication reserve Each volume requires primary group space for use during replication and, optionally, for storing the failback snapshot. • Delegated space To provide space for storing replicas, the secondary group delegates space to the primary group. All primary group volumes that you replicate to the secondary group share the delegated space. Each volume is assigned a portion of delegated space, called the replica reserve. The replica reserve for a volume limits the number of replicas you can keep. When replica reserve is consumed, the oldest replicas are deleted to free space for new replicas. To make sure replication operations complete and to keep the desired number of volume replicas, you must allocate sufficient replication space. To determine the optimal amount of replication space, Dell recommends that you set up replication using the default space values, monitor activity over some time period, analyze the space usage, and make adjustments. These precautions will help you keep the desired number of replicas while using replication space efficiently. About Local Replication Reserve Each replicated volume requires primary group space, called local replication reserve. See Figure 19. Local Replication Reserve. 248 About Backing Up and Protecting Your Data
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