This article indicates the FAST VP SRDF coordination feature description and  how to use Solutions Enabler and Unisphere for VMAX to configure FAST VP SRDF coordination. 

FAST VP SRDF coordination:

Since the FAST VP was introduced, the use of FAST VP with SRDF devices is fully supported. However FAST operates within a single array and therefore will only impact the RDF devices on that array. Previously there was no coordination of data movement between RDF pairs. Each device’s extents would move according to the manner in which where accessed on that array, source or target.

For instance, an R2 device will typically be subject to a read/write workload, which the R2 will only experience the writes that are propagated across the link from the R1. Because the reads to the R1 are not propagated to the R2, FAST VP on the R2 side will make its decisions based solely on the writes and therefore the R2 data will likely not be moved to the same tiers, in the same amounts, as on the R1.

To rectify this problem, EMC introduced FAST VP SRDF coordination in Enginuity 5876. FAST VP SRDF coordination allows the R1 performance metrics to be transmitted across the link and used by FAST VP engine on the R2 array to make promotion and demotion decisions. Both arrays involved with replication must be at Enginuity 5876 to take advantage of this feature. As the performance metrics is transferred through SRDF link. When the link is down, or SRDF status is split, suspended, failover or partitioned, the metrics is not sent to R2 array.

FAST VP SRDF coordination is supported for single and concurrent SRDF pairing (R1 and R11 devices) in any mode of operation: Synchronous, asynchronous, or adaptive copy. FAST VP SRDF coordination is not supported for SRDF/Star, SRDF/EDP, or Cascaded SRDF including R21 and R22 devices.

FAST VP SRDF coordination is enabled or disabled at the storage group that is associated with FAST VP policy. The default state is disabled.

To configure FAST VP SRDF coordination through Solutions Enabler, use following commands:

#symfast -sid [-i ] [-c ]-fp_name associate -sg [-priority ] [-rdf_coordination ]

#symfast -sid [-i ] [-c ]-fp_name modify -sg [-priority ][-rdf_coordination ]

                    

To configure FAST VP SRDF coordination through Unisphere for VMAX

Select the Symmetrix system.

Select Storage > FAST to open the FAST dashboard.

If the Symmetrix system is licensed for both FAST DP and FAST VP, select the FAST Type.

In the FAST Policies view block, click Manage Policies to open the FAST Policies details view.

Select the policy and click Associate Storage Group to open the Associate Storage Group dialog box.

Select one or more storage groups from the Available Storage Groups list and click Add to move them to the Associated Storage Groups list, or click Add All to move all storage groups from the Available Storage Groups list to the Associated Storage Groups list.

Click to Enable FAST VP RDF Coordination

Author: Fenglin Li

             

iEMC APJ