Most Recent Dell EMC DEE-1111 Exam Dumps

For an SRDF/Metro personality swap, the SRDF/Metro devices must be Read/Write (RW) on the link. This ensures that data can be read from and written to the devices during the swap operation.

An SRDF/Metro device pair was in an ActiveActive state, meaning that both the R1 and R2 devices were read/write accessible to the host or hosts. A link failure between arrays occurs, causing the device pair to become Not Ready (NR) on the SRDF link. SRDF/Metro responds by making the non-biased or R2 paired device inaccessible (not ready) to the host or host cluster, while keeping the biased or R1 paired device accessible (ready). This ensures that there is no data inconsistency or split-brain scenario between the two sites. The device pair enters an Active Bias state, which indicates that only one side of the pair is active and has a bias attribute set. The bias attribute determines which side of the pair remains accessible in case of a link failure. By default, the bias is set to the R1 side of the pair, but it can be changed using the symrdf set bias command. The application continues running on the R1 side, and the link failure is addressed. Once the link is restored, the device pair resumes the ActiveActive state and both devices become accessible again.

SRDF/Metro overview

VMware vSphere Metro Storage Cluster (vMSC) with Dell PowerMax and Dell EMC VMAX SRDF/Metro

Understanding bias

In a Concurrent SRDF/Star environment where the production data on R11 devices are replicated to two R2 devices in two remote arrays, SRDF/S links must be configured between Site 3 and Site 2. This is because in a Concurrent SRDF/Star configuration, there are two target sites and one source site.If there's a failure, the source site can switch to either of the target sites based on the business continuity plan1.Reference:Dell EMC Solutions Enabler 9.2 SRDF Family CLI User Guide,SRDF Star software uses and best practices - Dell

In an SRDF/Star configuration, all SRDF/Star device pairs must be of the same geometry and size. This is because SRDF/Star uses concurrent SRDF to maintain synchronous and asynchronous SRDF sessions between three arrays.The devices in these sessions must have identical geometry to ensure data consistency56.Reference:Dell EMC Solutions Enabler 9.2 SRDF Family CLI User Guide,SRDF/Metro overview | Dell EMC PowerMax and VMAX All Flash: SRDF/Metro Overview and Best Practices

In an SRDF/Metro configuration, if the host is cross-connected and the R2 device becomes Not Ready, the host continues to have read/write access to the R1 device12. This is because SRDF/Metro is designed to provide high availability and continuous data access.If one device becomes inaccessible, the host can still access the other device12.Reference:SRDF/Metro | SAP Landscape Consolidation with Dell Components,Understanding bias | Dell EMC PowerMax and VMAX All Flash: SRDF/Metro Overview and Best Practices