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A vdisk with a processing bottleneck will not be able to process user requests for data quickly, thereby causing prolonged delays in data access for users. Similarly, a vdisk that is overloaded will not be able to perform at peak capacity, thus affecting the user experience with the storage system. Administrators hence have to continuously track the load on and the processing speed of each of the vdisks, so that potential overload conditions and probable processing delays can be detected proactively and pre-emptively treated. The EMCPvMeVDiskTest helps administrators with this. This test monitors the level of traffic on each vdisk on a EMC PowerVault ME storage system, and helps isolate irregularities in load balancing across the vdisks. Alongside, the test also helps identify which vdisk is experiencing processing bottlenecks (if any), so that the bottleneck is cleared before users complain of slowdowns.

Measurement	Description	Measurement Unit	Interpretation
bytes_per_sec	Indicates the rate at which data is transmitted through this vdisk during the last measurement period.	MB/Second	This is a good indicator of the load on the vdisk. You can compare the value of this measure across vDisks to figure out whether the load has been distributed uniformly across all vdisks or a few vdisks are overloaded. In case of the latter, you may have to fine-tune the load-balancing algorithm used.
iops	Indicates the rate at which the I/O operations were performed by this vdisk during the last measurement period.	IOPS	This measure serves as a good indicator of the I/O processing ability of the vDisk. A consistent drop in this value is hence a cause for concern, as it indicates a processing slowdown.
num_reads	Indicates the rate at which the read operations were performed on this vdisk during the last measurement period.	Reads/Second	Ideally, the value of these measures should be high. A steady dip in these values could indicate a potential processing bottleneck that will have to be cleared immediately to ensure the normal transaction of business.
num_writes	Indicates the rate at which the write operations were performed on this vdisk during the last measurement period.	Writes/Second
data_read	Indicates the rate at which the data was read from this vdisk during the last measurement period.	MB/Second	Comparing the value of these measures across the vdisks will clearly indicate which vdisk is the slowest in terms of reading and writing. This way, you can quickly identify the vdisk that is experiencing a processing bottleneck.
data_writes	Indicates the rate at which the data was written from this vdisk during the last measurement period.	MB/Second