Administrator Guide

For disaster recovery on NAS containers, after you fail over to the destination container, you can fail back to the primary container in
a single-step process.
A properly congured system does not require a conguration restoration to perform a failover operation. However, if the source
cluster conguration needs to be applied to the destination cluster, contact Dell Technical Support for assistance.
Fail Over to a Recovery Volume
Failing over to a recovery volume prepares storage resources to recover data that was replicated to a replica volume. A primary
volume does not have to be available until the end of this process.
The process of performing a failover to the replica volume:
• Removes the replication partnership dened between the primary and replica volumes.
• Promotes the replica volume to a recovery volume, enabling clients to read and write directly with the recovery volume, instead
of the primary volume.
• Denes a replication partnership between the recovery volume and a primary volume, enabling data to be restored from the
recovery volume to a primary volume.
– If the original primary volume is not immediately available, this partnership can be dened after the primary volume becomes
available.
– If the original primary volume is no longer available, this partnership is dened between the recovery volume and a new
primary volume.
– For example: Primary volume A is congured in a replication partnership with volume B. If volume A is no longer available, as
part of the failover process, volume B can be congured with a new primary volume, volume C.
NOTE: The recovery volume’s data is complete up to the point in time of the most recent successful replication.
If user and group quota rules are in place for the source volume, those quotas are applied to the recovery volume as follows:
• If an external server (such as Active Directory, LDAP, or NIS) is authenticating users and groups on the destination cluster,
quotas are applied to the recovery volume.
• If only local users and groups are used, quotas are not applied.
• If local users and groups are used and an external server authenticates users and groups, user and group quotas are applied for
the externally authenticated accounts. However, you must verify that quotas are applied correctly for the local users and groups.
If they are not applied correctly, modify them so that they are correct.
Access Replica Container Data
To grant hosts access to the contents of a replica container, or fail over to the NAS replica container, select the Apply Host Access
Conguration option. After you perform that operation, hosts that had access to the source container are granted access to the
recovery container.
Fail Over to the NAS Destination Cluster
When a disaster occurs in a NAS network and the source NAS cluster becomes unavailable for some reason, you must fail over to
the destination (or replica) NAS cluster, as shown in Figure 31. NAS Replication Failover.
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