Sizing the SRL

The size of the SRL is critical to the performance of replication. This section describes some of the considerations in determining the size of the SRL.

You can use the Volume Replicator Advisor (VRAdvisor) tool to help determine the appropriate SRL size.

See How VRAdvisor works.

If the SRL overflows and SRL protection is not enabled, the RLINK is marked STALE,. Otherwise, if SRL protection is set to autodcm or dcm, the RLINK is disconnected and it goes into DCM mode. Because resynchronization is a time-consuming process and during this time the data on the Secondary cannot be used, it is important to avoid SRL overflows. The SRL size needs to be large enough to satisfy four constraints:


Regardless of the replication mode, the SRL size must be at least 110 MB. If the size that you have specified for the SRL is less than 110 MB, VVR displays an error message which prompts you to specify a value that is equal to or greater then 110 MB.

To determine the size of the SRL, you must determine the size required to satisfy each of these constraints individually. Then, choose a value at least equal to the maximum so that all constraints are satisfied. The information needed to perform this analysis, presented below, includes:


If the Automatic Synchronization option is used to synchronize the Secondary, the previous paragraph is not a concern.

If you are going to perform Secondary backup to avoid complete resynchronization in case of Secondary data volume failure, the information needed also includes: