|
Measures reported by HitachiRaidTest
"RAID" - the Redundant Array of Independent Disks - is now used as an umbrella term for computer data storage schemes that can divide and replicate data among multiple hard disk drives. RAID's various designs all involve two key design goals: increased data reliability or increased input/output performance. When multiple physical disks are set up to use RAID technology, they are said to be in a RAID array/group. This array distributes data across multiple disks, but the array is seen by the computer user and operating system as one single disk.
For every RAID group auto-discovered on a Hitachi AMS storage device, this test monitors the I/O load on the group.
This test is used to monitors the I/O load on each RAID group.
The measures
made by this test are as
follows:
| Measurement |
Description |
Measurement
Unit |
Interpretation |
| IO_Rate |
Indicates the number of read/write commands executed on this RAID group per second.
|
IOPS |
If this measure reports a high value or if the value of the measure increases consistently, it is indicative of unusually high I/O activity on this RAID group. Comparing the value of this measure across groups can accurately indicate which RAID group is currently experiencing heavy workloads. Observing the variations in this measure over a period of time will enable you to figure out bottlenecks in load balancing.
|
| Read_Rate |
Indicates the number of read operations performed on this RAID group per second.
|
IOPS |
|
| Write_Rate |
Indicates the number of write commands issued on this RAID group per second.
|
IOPS |
|
| Read_Hit |
Indicates the percentage of read requests that were served from this RAID group.
|
% |
Ideally, the value of this measure should be high. A low value is a cause for concern, as it indicates that a majority of read requests have failed.
|
| Write_Hit |
Indicates the percentage of data written to this RAID group.
|
% |
Ideally, the value of this measure should be high. A low value is a cause for concern, as it indicates that not all data is getting written to this RAID group; this could be owing to an I/O bottleneck, which might require further investigation.
|
| Trans_Rate |
Indicates the transfer size of read/write commands per second.
|
KB/sec |
|
| Read_Trans_Rate |
Indicates the transfer size of read commands per second.
|
KB/sec |
|
| Write_Trans_Rate |
Indicates the transfer size of write commands per second.
|
KB/sec |
|
|