eG Monitoring
 

Measures reported by EMCPvMeDiskTest

Processing bottlenecks in disks can significantly delay reading from and/or writing to the disks, affecting user experience with the storage system as a whole. If this is to be prevented, administrators need to keep a close watch on the I/O activity on each disk of the storage system, detect a slowdown well before users notice it, and take pre-emptive action. The EMCPvMeDiskTest can help administrators achieve this. This test monitors the level of I/O activity on each physical disk mounted on a EMC PowerVault ME storage system, helps isolate overload conditions or processing latencies in the disks.

Outputs of the test :One set of results for each physical disk of the EMC PowerVault ME storage system being monitored.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
bytes_per_sec Indicates the rate at which data is transmitted through this disk during the last measurement period. MB/second This is a good indicator of the load on the disk. You can compare the value of this measure across disks to figure out whether the load has been distributed uniformly across all disks or a few disks 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 through this disk during the last measurement period. IOPS This measure serves as a good indicator of the I/O processing ability of the disk. 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 disk during the last measurement period. Reads/Second Ideally, the value of this measure should be high. A steady dip in this measure value could indicate a potential reading bottleneck. By comparing the value of this measure across disks, you can quickly identify that disk which is the slowest in processing read requests.
num_writes Indicates the rate at which the write operations were performed on this disk during the last measurement period. Writes/Second Ideally, the value of this measure should be high. A steady dip in this measure value could indicate a potential writing bottleneck. By comparing the value of this measure across disks, you can quickly identify that disk which is the slowest in processing write requests.
data_read Indicates the rate at which the data was read from this disk during the last measurement period. MB/Second Comparing the value of these measures across the disks will clearly indicate which disk is the busiest in terms of data transmission - it could also shed light on irregularities in load balancing across the volumes.
data_writes Indicates the rate at which the data was written from this disk during the last measurement period. MB/Second
queue_depth Indicates the number of pending I/O operations that are currently being serviced on this disk. Number A consistent rise in the value of this measure indicates a processing bottleneck at the disk that is causing I/O requests to queue up.