The graph provided in the exhibit shows a high level of ‘Sent’ bandwidth usage, which remains consistently near the upper limit of the chart. This suggests that there is a significant amount of data being sent over the WAN link. In a Dell VPLEX environment, if virtual volumes created on distributed devices experience performance problems, one possible reason could be that I/O demands exceed available WAN COM (WAN Communication) bandwidth.
Here’s a detailed explanation:
High ‘Sent’ Bandwidth Usage: The graph indicates that the ‘Sent’ bandwidth is consistently high, nearing the chart’s maximum capacity.
Impact on Performance: When the I/O of a distributed device exceeds the available WAN COM bandwidth, it can cause a bottleneck, resulting in performance issues such as increased latency or slower response times for write operations.
VPLEX Distributed Architecture: In a VPLEX distributed environment, data must be written to both clusters before an acknowledgment is sent to the host. If the WAN link is saturated, this process is delayed, affecting overall performance.
Monitoring Tools: VPLEX provides monitoring tools that can help identify such issues. The graph in the exhibit likely comes from such a tool, illustrating the system-wide WAN link usage and pinpointing potential performance bottlenecks.
Resolution: To resolve this issue, a storage administrator might need to consider increasing the WAN COM bandwidth, optimizing the data flow, or redistributing the workload to reduce the strain on the WAN link.
References:
Dell EMC VPLEX documentation regarding system performance considerations discusses factors affecting virtual volume performance, including network constraints.
Best practices for VPLEX suggest monitoring WAN link usage and ensuring it aligns with the expected performance levels for distributed devices.
By analyzing the WAN COM bandwidth usage and understanding its impact on distributed device performance, storage administrators can take appropriate actions to mitigate any issues and maintain optimal performance levels.