eG Monitoring
 

Measures reported by LHVolumePerfTest

This test auto-discovers the volumes in the target storage cluster and reports how well each volume handles the I/O requests it receives. In addition, this test reveals the time taken to complete read and write operations on each volume. This way, the test turns the spotlight on volumes that are experiencing a slowdown and also reveals what is causing the slowdown - load-balancing irregularities across volumes or poor I/O processing capability?

Outputs of the test : One set of results for each volume on the target storage cluster being monitored.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
IO_reads Indicates the rate at which read I/O operations were performed on this volume during the last measurement period. Operations/sec Ideally, the value of this measure should be high. A steady dip in this measure value could indicate a potential reading bottleneck.
IO_writes Indicates the rate at which write I/O operations were performed on this volume during the last measurement period. Operations/sec  
Total_IO Indicates the total read and write I/O operations performed on this volume during the last measurement period. Operations/sec This measure serves as a good indicator of the I/O processing ability of the volume. A consistent drop in this value is hence a cause for concern, as it indicates a processing slowdown.
Data_reads Indicates the rate at which data was read from this volume. MB/sec Comparing the value of these measures across the volumes will clearly indicate which volume is the busiest in terms of the rate at which data is read and written - it could also shed light on irregularities in load balancing across the volumes.
Data_writes Indicates the rate at which data was written to this volume. MB/sec
Data_processed Indicates the overall rate at which data was read from and written to this volume. MB/sec  
Pending_read_ops Indicates the rate at which read I/O operations were pending on this volume during the last measurement period. Operations/sec  
Pending_write_ops Indicates the rate at which write operations were pending on this volume during the last measurement period. Operations/sec  
Pending_IO_operation Indicates the overall rate at which read and write I/O operations were pending on this volume during the last measurement period. Operations/sec  
Read_latency Indicates the time taken to complete the read I/O operations on this volume. Millisec  
Write_latency Indicates the time taken to complete the write I/O operations on this volume. Millisec  
Cache_hits Indicates the rate which read operations were serviced from the cache of this volume. Operations/sec Ideally, the value of this measure should be high. A consistent drop in cache hits and a steady increase in cache misses during the same time frame is indicative of ineffective read cache usage, which can lead to a slowness in read request servicing.